1. Restore a backup
Import a JSON backup file to bring back your previously saved plan.
No local plan found
SimuPlan stores plans locally in your browser. If storage was cleared, you switched browsers or devices, or you're using incognito mode, your saved plan won't appear unless you restore a JSON backup.
Sample data is not your saved plan. It's a demo workspace to help you explore SimuPlan when no local plan is available.
Local-first. Private by design.
No account required. No cloud sync. Your data stays on this device.
Welcome to SimuPlan
We'll walk you through a few simple steps to set up your plan. You can change anything later.
All your data is stored in your browser and never leaves your device. You're in control, always.
Tell us about yourself and your household.
Add your accounts, balances, income, and cash-flow basics.
Define your retirement age and spending goals.
Review and adjust key planning assumptions.
Review your plan and you're all set.
Start with the profile details that anchor your plan's timeline, tax assumptions, and application mode.
Choose the planning lane that best matches where you are today.
This information helps personalize your plan and ensures our assumptions match your situation. You can update any of this anytime.
Capture the basics: what you have now, what comes in, and what you expect to spend.
Estimate your current totals by planning bucket. This gets the first projection moving. After setup, you can add real account details manually.
Prefer importing spreadsheets? Settings and Plan Tracking include a balance import tool and sample file format.
Have another account type? Start with the closest total here, then fine-tune the account details in Settings after the starter plan is built.
Start with current earned income and any known retirement income. For a two-person household, enter combined earned income for now; you can split it later in Settings > Profile.
Start with the income sources already supporting a fully retired household. If anyone still earns wages, return to About You and choose Planning for Retirement.
Add the regular monthly amount you expect to save or contribute before retirement.
Set the checking balance you want to keep available for near-term bills. SimuPlan uses this as your operating-cash cushion when tracking withdrawal needs.
Balances, income, and cash-flow basics create the first version of your plan. Timing choices, detailed account rules, taxes, and withdrawal preferences can be refined later.
Set the timing and lifestyle target SimuPlan should build around.
When would you ideally like retirement to begin?
Your household retirement plan begins today.
Different work-end dates? Enter the household's starter retirement age here. After saving, use Settings > Profile to assign each person's work-end age, earned income, and contributions.
Is anyone in the household still working? Return to About You and choose Planning for Retirement. Household Retired Now assumes everyone in the household is already retired.
Start with the monthly lifestyle you want the plan to support, in today's dollars.
Need spending to change over time? You can add higher-spending go-go years, lower-spending slow-go years, and one-time retirement expenses later in Settings.
Tell SimuPlan when Social Security should begin for each person in the household.
If you are already receiving Social Security, enter your current age. You can refine claiming assumptions later in Settings.
Retirement target
Enter the retirement target balance you want this plan to work toward. You can change it later in Settings.
Suggested retirement-age target: — Complete retirement timing and monthly spending above to see an estimate.
Goals tell SimuPlan what the money is meant to do. Start with your best estimate now, then use Settings later for finer control.
Use balanced defaults, or adjust the few assumptions that matter most to the starter projection.
These are the starter assumptions the projection actually uses.
Returns are set by starter account bucket. You can refine individual account returns later in Settings.
Taxes, Social Security COLA, ACA MAGI cap estimates, Medicare age, RMD rules, penalty-free withdrawal age, withdrawal order, and spending basis use SimuPlan's starter defaults.
After the starter plan is built, Settings gives you finer control over each of these assumptions.
Returns and inflation are the assumptions most likely to move a starter projection. Choose reasonable starting assumptions here, then use scenarios later to test different futures.
Name this starter plan, save it as your first scenario profile, and keep a backup option close by.
Starter plan profile
Saved scenario profiles let you come back to this starting point, compare future versions, and experiment without losing your baseline.
Ready to save this starter plan in your browser.
Planning for Retirement Applies when anyone in the household is still working or retirement begins in the future.
Household Retired Now Applies only when everyone in the household is already retired today.
Starter balances, income, and contribution or withdrawal basics give the plan its first cash-flow shape.
Retirement timing, Social Security timing, and lifestyle target guide the projection.
Returns and inflation start with balanced defaults you can refine later.
Recommended next (optional)
The totals you entered into Your Finances are enough to get the projection started. SimuPlan comes alive when it has real account information to compare against the projection though. Consider adding that now, or later once you're in the app.
Prefer importing spreadsheets? After setup, Settings and Plan Tracking include a balance import tool and sample file format.
A backup protects your plan if browser data is cleared. It also gives you a portable file you can load on another computer or share with a financial advisor.
The dashboard gives you the first readout. Plan Tracking compares any real balances you add against your projection, and Settings is where you can add detail, tune tax rules, and make the starter plan more personal.
Track how the latest imported balance compares with the retirement starting target you are planning toward.
A quick read on readiness, savings pace, and the projected cushion around your retirement target.
Year -- status from withdrawals, estimated taxes, and MAGI-relevant taxable sales.
Quick simulation readout from the current plan.
Waiting for the current Monte Carlo snapshot.
Half of the simulation paths finished above this ending balance and half below it.
The 10th-percentile ending balance: about 1 in 10 paths finish below this amount.
Share of paths that reached the retirement target by the planned retirement age.
Once the plan loads, this space will surface a useful place to explore next.
Explore the workspaceThis chart mixes annual flows and ending balance in one view. Hover a year group to preview a local zoom. Click a year group to pin that six-year window.
Hover a year group to preview nearby years. Click a year group to pin its six-year window.
The chart shows whether modeled growth is outpacing portfolio cash used.
Projected balances stay visible across the full planning window.
Click a year group to pin its local window and inspect the money-flow story.
How to read this page
Projections start from the latest saved balance, then carry your plan assumptions forward to estimate whether retirement still works.
Plan Tracking can look different because it checks whether real imported balances have been matching the plan month by month.
Follow the portfolio from today, through the retirement transition, to the end of the active planning window.
Starting point across the active household accounts.
Projected balance where the plan switches phases.
Final year in the active projection window.
These cards are driven primarily by your plan inputs and assumptions, using your latest saved balance snapshot as the current starting point when balance history is available.
This row compares your retirement target with the planner's projected balance, then translates the gap into readiness and spending cushion.
This row shows how your current income and contribution plan are supporting progress toward your retirement goal.
This row shows the main levers you can change if you want to improve the outcome: save more, earn a higher return, or retire later.
Monthly balance snapshots translated into projected surplus or shortfall at retirement.
This view focuses on your balance path to retirement first. Subsidy and MAGI details move to the retirement health section until they become relevant.
This report breaks your retirement plan into a clear, year-by-year story.
Each row is a rolling 12-month projection block. Click any year to open the Money Flow Story and see how that year was built.
See exactly how the start balance becomes the end balance. We show what added money, what used money, and the impact of taxes and withdrawals.
Go beyond the numbers. Understand why taxes were triggered, how MAGI was built, and how taxable basis affects brokerage withdrawals.
Tip: Click any row in the timeline to open the full story for that year. The more detail you explore, the clearer your retirement picture becomes.
How to read this page
Plan Tracking compares imported balance history with where the projection expected the portfolio to be by the same month.
Projections may still show the plan working if future contributions, time, and return assumptions recover a short-term tracking gap.
The latest imported snapshot is matched against the projection so you can see whether real balances are tracking ahead of or behind plan.
Recommended first step
Your starter balances are powering the projection, but Plan Tracking needs at least one real dated balance snapshot before it can compare actual progress against the plan.
Add your first snapshot manually now, or use spreadsheet import if you already track balances elsewhere.
Latest imported balance, recent movement, and how the money is grouped for planning.
Waiting for imported balance history.
Import at least two snapshots to show the comparison window.
Add one more monthly balance snapshot and this card will compare your most recent snapshot against the prior month.
Grouped to match the buckets your projection uses.
Import at least two snapshots to show the comparison window.
Imported snapshots are matched to the projection month, then compared against the plan and retirement target.
Plan Tracking compares real balances against the matched projection month. Projections carry the latest balance and assumptions forward to estimate the retirement outcome.
Add a real balance snapshot to calculate the next withdrawal suggestion.
Import balance history to compare actual balances against the matched projection month.
Add a retirement target balance to estimate the gap.
Recorded history provides the basis for plan comparisons.
Needs matched imported snapshots.
Trend-based estimate will appear once imported balance history is available.
Keep your plan current and your data protected.
Your plan lives in this browser. Download a JSON backup before clearing browser data or switching computers.
Ready for your next balance update.Compare recorded investment and savings balances with the pace implied by the plan's return assumptions. Accounts need enough history and a return assumption to appear here; checking accounts set to 0% are not included.
These are annualized balance-growth estimates, not calculated investment returns. Actual pace includes every recorded balance change. Adjusted pace subtracts planned contributions over the tracking period; other balance activity and timing may still affect it. Expected pace applies the plan's current return and contribution assumptions across the full tracking period.
Imported accounts grouped into the same planning buckets used by projections.
Import at least two snapshots to show the account comparison window.
Planned balance (projection) versus imported actuals. The gap shows how closely your real balances are tracking against the plan.
Staying close to plan over time is a useful confidence signal that your real balances are moving in line with the projection and your inputs reflect real-world income, saving, and spending patterns.
Track health and tax planning for the active household mode.
See how much income you're expected to have and how it impacts your MAGI.
We track your MAGI room and show how close you are to key thresholds.
Use the ledger and quarterly tax workspace to plan ahead and avoid surprises.
Your current-year MAGI room and withdrawal room are tracked side by side, so taxable sales, spending, and subsidy thresholds stay visible before they become a problem.
You are within your MAGI limit.
You are within your safe withdrawal range.
Projected retirement income, interest, dividends, taxable sale income, and remaining MAGI room are translated into a simple equation against your current-year MAGI cap.
A dedicated home for estimated federal/state tax calculations and payment reminders.
Compare saved scenario branches, ask focused diagnostic questions, or build a temporary query against the current plan.
Saved scenarios are branches you can compare. Diagnostic questions are answer-first tests. Custom queries combine temporary inputs before you decide what to save.
The current plan and saved scenario must use the same planning mode and simulation length so the comparison stays apples-to-apples.
Only compatible saved scenarios are shown.
Question mode
These questions test the current plan with focused evidence so you can understand timing, spending, taxes, withdrawal pressure, and durability.
Choose a question category
Browse categories or pick from popular questions to get started.
Popular questions
Popular questions to get started quickly.
Retirement Resilience Review
The review runs every applicable stress test against your current saved plan. It identifies which tests stay within the review rules, ranks those that do not, and then tests practical responses against the highest-priority result.
The answer may be a change that restores the result—or confirmation that keeping your current plan is the strongest tested choice.
The review tests earlier retirement, higher spending, inflation, weaker returns, large expenses, poor early markets, and other conditions your plan can model.
Each pressure is checked using randomized future paths, historical market periods, and the review’s plan-funding rules.
If multiple tests fall below a rule, the review ranks them so the most important concern is investigated first.
How priority works: funding and survival concerns come first.The review tries changes such as retiring later, spending less, or saving more. It shows what passed, what helped, and whether keeping the current plan was the strongest tested response.
Create or save a retirement plan before running the resilience review.
Open Plan assumptionsCustom query mode
Choose one or more temporary inputs, tune each assumption, and run them together against the current plan. Save only the results you want to keep as a scenario branch.
Temporary test setup
Select a question above to build a temporary test against your current plan.
Choose a compatible saved scenario branch, then launch the analysis to compare it with the current plan.
Saved scenario branch and current plan over the full projection window.
Full scenario comparison report, including setup differences, projection outcomes, taxes, and stress-test results.
Scenario B is compared directly against Scenario A, with the Difference column showing how much Scenario B moves each metric.
| Metric | Current plan | Test result | Change |
|---|
Simulation Lab
Use Simulation Lab to stress test your current loaded plan. Begin by selecting the number of simulations to run.
Model thousands of possible futures using randomized returns and historical market data.
Understand upside, downside, and everything in between with clear probability bands.
Explore market volatility, sequence of returns, and timing risk against your current plan.
Use simulation evidence to make smarter decisions and stay on track for your goals.
Simulation Lab
Launch simulations once, then inspect each view as a different slice of the same evidence.
This triage run combines randomized futures, historical rolling windows, and famous market replays into one stress verdict, then points toward the view that deserves closer inspection.
Checking randomized futures, historical windows, and famous market replays against the active plan.
Launch simulations to see the plan through three different risk views.
Launch simulations to total the funded paths across all views.
Waiting for randomized futures.
500 futures after launch.Launch simulations to identify the weakest randomized path.
Tests every full-length rolling block available for the projection length.
Historical windows after launch.Launch simulations to identify the weakest historical window.
Waiting for famous replay results.
Recognizable stress periods.Launch simulations to identify the weakest market replay.
Monte Carlo View
Switch between randomized futures and rolling historical windows from the latest simulation run, then select any path to inspect its balance story and return sequence.
Monte Carlo View
Switch between randomized futures and rolling historical windows from the latest simulation run, then select any path to inspect its balance story and return sequence.
Randomized futures are generated from the active return assumptions.
Half of randomized futures end above this amount and half below it.
The 10th-percentile ending balance: about 1 in 10 futures finish below this amount.
Largest observed fall from a prior high across the run.
The top upside paths: strongest ending balances, then the drivers that helped them compound.
The paths most worth inspecting first: depletion, largest target shortfalls, then lowest cushion.
Outcome distribution
Where the randomized futures cluster at the end of the planning window. Numbers above bars show futures counts.
Futures report
Review every synthetic path from the latest simulation run, then filter by outcome or select a future to inspect its balance story below.
Launch simulations to populate outcomes.
Inflation path
Spending follows the monthly CPI changes aligned with every rolling market window, including deflation. This is the default recommended setting.
What changes? With Historical CPI on, spending follows the month-by-month inflation path that occurred alongside each rolling market window. With it off, every window uses your plan's fixed annual inflation assumption.
Why is it recommended? Replaying returns and inflation together gives a more complete view of the purchasing-power pressure households actually faced during each period.
Why can results move either way? Inflation shocks can raise spending and withdrawals when markets are already under pressure. Lower inflation or deflation can reduce spending pressure, so some historical windows may improve.
What stays unchanged? Income sources and healthcare costs that have their own growth settings continue to use those plan settings.
Comparing an older report? Historical windows previously used your plan's fixed inflation assumption. Turn Historical CPI off to compare using that earlier methodology.
The historical view scans every full-length rolling block in the annual return data.
The middle outcome across all historical windows.
The 10th-percentile ending balance: about 1 in 10 historical windows finish below this amount.
Largest drawdown observed across historical windows.
The top upside windows: strongest ending balances, then the historical return drivers that helped them compound.
The historical windows most worth inspecting first: depletion, largest target shortfalls, then lowest cushion.
Outcome distribution
Where the historical windows cluster at the end of the planning window. Numbers above bars show window counts.
Historical report
Review every rolling historical window from the latest simulation run, then filter by outcome or select a period to inspect its balance story below.
Launch simulations to populate outcomes.
Selected replay
Select a replay to inspect the result.
Historical backdrop
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These are the historical pressure points this replay front-loads into the plan.
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The replay shows how market timing affects the path to retirement.
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Control the details that drive your plan and see how small changes can shape your future.
Household size, birth month / year, retirement timing, and employer coverage.
Monthly spending and planned expense assumptions.
Social Security, pensions, annuities, income sources, and working-year earned income.
Medicare, subsidy thresholds, MAGI deductions, and income-sensitive planning assumptions.
Filing status, state, tax rates, Social Security taxation, and tax-estimate mode.
Withdrawal methods and tax optimization rules.
Projection years, inflation, baseline, target, and age rules.
Account buckets, balances, return assumptions, contributions, and imported balance behavior.
Saved plan versions, reloadable branches, and scenario comparisons.
Balance imports, starter files, reports, backups, restore actions, and maintenance tasks.
PRO TIPS
Download a fresh backup after meaningful plan edits so you always have a clean restore point.
Retirement age, monthly spending, inflation, and expected returns usually move the forecast more than fine-tuning small details.
If you are changing several assumptions at once, save a scenario first so Scenario Lab can compare the branches cleanly.
Fresh balance snapshots make Plan Tracking more useful because the app can compare real progress against the projection path.
Update the household profile and timing assumptions that anchor the rest of the plan.
Current assumption.
Controls which fields are relevant.
Changes flow into scenarios and simulations.
Jump to another settings area without returning to the overview.
These fields define household size, birth month / year, retirement timing, and employer coverage assumptions.
Choose one shared retirement timeline, or model when each person stops working.
Earned income and assigned account contributions currently stop together when household retirement begins.
These assumptions drive working-year savings, retirement cash flow, tax estimates, and MAGI-sensitive planning.
Used for savings-rate and working-year income diagnostics while the household is still working.
Social Security, pension, annuity, and recurring income assumptions that reduce required portfolio withdrawals.
Claim age, manual or estimated benefit, spouse benefit, and annual COLA.
Pension, annuity, and other recurring income sources.
Set the household spending need that the projection tries to support.
Track income-cap pressure for pre-Medicare bridge years and other MAGI-sensitive planning.
Used only for the HHS FPL ACA MAGI cap estimate. This does not change tax filing, Social Security, or spouse modeling.
Auto-estimate uses filing status and state. Custom rates let advanced users override tax drag directly.
Estimated from federal brackets, filing status, and taxable ordinary income.
Estimated from federal capital gains rules, taxable brokerage activity, and NIIT when applicable.
Estimated from your selected state and the plan's taxable income mix.
Built from the active federal and state tax rules included with this app.
Review the active account buckets, imported balances, return assumptions, contribution settings, and tax treatment.
Set the projection window, inflation assumption, balance targets, and age-based retirement rules.
Choose the default order for funding retirement spending and the guardrail method for Household Retired Now planning.
Starts at a 4% withdrawal rate, watches a 20% guardrail band, and adjusts the next year's base spending by 10% when the plan moves outside the band.
Most users should leave these alone. Change them only when you want to compare a specific custom interpretation of the strategy.
Saved scenarios are plan branches you can reload, compare, and return to after testing changes.
Use this when the current plan is a branch you may want to compare or return to later.
Load a branch, copy it, rename it, or remove scenarios you no longer need.
Pick two saved scenario branches to scan which planning inputs changed.
Import balances, export backups, and keep browser-based plan data protected.
Import account balances from a CSV or XLSX file. We'll match and add the data to your plan.
Use the sample file to see the supported spreadsheet columns, account aliases, and balance history layout before importing.
Download sample CSVAdd a new monthly balance snapshot manually for one or more accounts.
Download a complete backup of your plan, settings, scenarios, and imported data (JSON file).
Restore a previously saved SimuPlan backup file. This will replace your current plan.
Export your imported balance history to CSV for your own records or for use in other tools.
SimuPlan stores your data locally in your browser.
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SimuPlan stores your plan directly in your browser instead of on a cloud server.
This approach was chosen intentionally. It keeps your data under your control, eliminates the need for accounts and passwords, and avoids the privacy concerns that come with storing personal financial information online. Your plan never leaves your device unless you choose to export it.
Because SimuPlan is built and maintained by a single independent developer, a local-first design also avoids the cost, complexity, and security responsibilities of operating cloud infrastructure, managing authentication systems, protecting user databases, and maintaining account aggregation connections. That allows more time to be spent improving planning tools rather than maintaining backend services.
Local storage is surprisingly efficient. A typical plan containing settings, scenarios, and imported balance history often uses only a small fraction of available browser storage. The largest contributors to storage usage are:
Simulation results, Monte Carlo runs, and comparison reports are intentionally treated as temporary analysis and generally are not permanently stored, helping keep storage requirements small.
Most browsers provide several megabytes of storage for local applications. SimuPlan monitors usage and provides backup tools so you can export your work whenever you wish.
For added peace of mind, consider downloading a JSON backup after important imports or major planning changes. A backup allows you to restore your plan later, move it to another computer, or keep a historical copy of your work.
Your data. Your device. Your control.
PRO TIPS
Use this as the regular household spending baseline.
Choose how the monthly spending number should be interpreted.
Add larger planned expenses only when they should not be part of the monthly baseline.
Model transparency
SimuPlan does not try to predict the future perfectly. It builds a clear planning model from your inputs, then shows how that model behaves under different assumptions.
The goal is to help you understand the moving parts: balances, contributions, spending, taxes, income, account types, market returns, and timing choices. When those assumptions change, SimuPlan shows how the outcome changes too.
Core model
SimuPlan looks at your plan from several angles. Each method answers a different question, so results may not always point in the same direction. That is normal, especially when markets are volatile or recent balance history differs from long-term assumptions.
The central projection is SimuPlan's baseline path. It starts with your latest saved or imported balance, then moves the plan forward year by year using your contributions, spending, income, taxes, inflation, account returns, and retirement timing.
Contribution timing: For projection purposes, planned monthly contributions are treated as arriving at the beginning of each modeled month, before that month's investment return is applied. Calculators that assume contributions arrive at month-end may show a slightly lower ending balance, especially over long periods. The total contributed does not change; only the timing of modeled growth differs.
What to remember: This is a planning baseline, not a market forecast.Plan Tracking compares your imported real-world balance snapshots with where the projection expected you to be at the same point in time. It is a near-term reality check, not a full re-projection of the future.
What to remember: A recent month can look behind plan even when the long-term projection still recovers under current assumptions.Monte Carlo simulations create many possible market paths around your expected-return assumptions. SimuPlan can use either its standard randomized model or an optional asset-aware model based on confirmed investment mixes.
What to remember: Randomized results test market uncertainty and timing risk. They are stress tests, not guarantees.Historical replays test your plan against real market patterns from the past, including difficult periods like recessions, inflation shocks, and major drawdowns. They use a Robert Shiller-based market return dataset and currently include complete annual market history through 2025.
Inflation treatment: Rolling historical windows can replay the monthly CPI path that occurred alongside each market sequence. This is the recommended setting for a complete historical comparison. You can instead hold spending growth to the plan's fixed inflation assumption to isolate market sequence risk. Income sources and healthcare costs that have their own growth settings continue to use those settings.
What to remember: History is useful context, but future markets will not repeat the past exactly.Retirement Resilience Review is SimuPlan's full-plan evaluation. It checks the saved plan against explicit funding rules, runs every applicable pressure through deterministic, randomized, and historical validation, ranks the results, and tests practical responses against the highest-priority concern.
Where to find it: Open Scenario Lab, choose Run resilience review, and start the review from that panel.
What to remember: This is a synthesis of SimuPlan's existing models—not a fifth projection engine—and it does not change the saved plan.Randomized model detail
SimuPlan offers two ways to generate randomized market paths. Both begin with the expected returns entered in your plan, but they model market movement differently.
If any funded investment account that needs clarification does not have a confirmed investment mix, SimuPlan uses its standard randomized model for the entire run. This model varies account returns around the plan's expected-return assumptions without trying to identify the stocks and bonds held inside each account.
This remains the default so users can create and test a plan without researching account allocations first.
Once every flagged funded account has a confirmed investment mix, SimuPlan weights those mixes using the accounts' current balances. Each randomized future then creates shared stock, bond, and cash market movements. Accounts exposed to the same type of investment can rise and fall together instead of receiving unrelated market results.
An account identified as single-company stock also receives additional generic concentration risk. SimuPlan does not forecast or replay the performance of the named company.
The selected randomized model is used consistently anywhere the full plan requests randomized futures, including Simulation Lab, Scenario Lab, Retirement Resilience Review, and applicable Plan Report results. SimuPlan does not combine the two randomized models within one run. If a new funded account later needs a mix—or an existing account is changed back to “Not confirmed”—the standard model is used until the optional setup is complete again.
Full-plan review
The review is designed to answer a broader question than one scenario or simulation: which tested condition deserves the most attention, why did it matter, and what practical responses improved the result?
The current plan is checked first. Planning for Retirement and Household Retired Now use different, mode-appropriate funding rules.
Each supported pressure receives the same deterministic projection, randomized future paths, and rolling historical-window review. Historical windows use historical CPI when that data is available.
The review gives priority to central-projection depletion, then portfolio-survival failures, the number of missed rules, and the size of the largest rule shortfall. A consistent tie-breaker resolves otherwise equal results.
Applicable responses—such as changing retirement timing, spending, saving, income, or spending flexibility—are rerun against the highest-ranked pressure using the same validation process.
Planning for Retirement
Household Retired Now
Rules and boundaries
SimuPlan includes enough detail to support useful planning comparisons without trying to become tax software, Social Security filing software, or a professional advisory system. The goal is to help you understand the tradeoffs, spot important planning questions, and know when something deserves a closer look.
SimuPlan estimates the major tax items that commonly affect retirement planning: federal ordinary income tax, capital gains and dividends, state tax, taxable Social Security, MAGI, ACA MAGI room, IRMAA room, RMD effects, and selected retirement-income exclusions.
What to remember: These estimates are designed for planning comparisons. They do not cover every deduction, credit, local tax, estate rule, inherited-account rule, or future tax-law change.
SimuPlan can estimate primary and spouse benefits, compare claiming ages, and apply annual Social Security cost-of-living adjustments.
What to remember: SimuPlan helps compare broad claiming choices, but it does not yet perform full household claiming optimization, survivor benefit optimization, or every Social Security edge case.
Roth Lab compares conversion-year tax cost, future RMD tax relief, MAGI and ACA guardrails, IRMAA room, and the projected result versus making no Roth conversions.
What to remember: Roth Lab does not tell you what to do. It helps size the tradeoff, identify possible benefits, and highlight risks worth reviewing before taking action.
Household Retired Now is intended only when everyone in the household is already retired today. It helps compare actual withdrawals, checking-buffer needs, taxable-sale room, annual guardrail room, and Guyton-Klinger style spending adjustments.
What to remember: These guardrails are planning signals. Spending choices remain assumptions unless you create or save a scenario that changes the plan.
Tax assumptions
SimuPlan starts with currently loaded tax tables and threshold assumptions. Officially indexed federal and state values grow into future projection years; future-law risk is tested with Scenario Lab stress inputs rather than predicted as a specific law change.
| Area | Modeled basis | Simplified or beyond scope |
|---|---|---|
| Federal income tax | Loaded 2026 federal tax tables, ordinary income, capital gains/dividends, taxable Social Security, and standard planning deductions. | No return preparation, itemized deduction planning, every credit, every surtax, or forecast of future federal law. |
| State income tax | State-specific profiles for broad income tax treatment and selected retirement-income exclusions. When state law officially indexes a modeled bracket, deduction, or threshold, future projection years grow that value using the plan's inflation assumption. | Local taxes, every state credit/deduction, state-specific edge cases, and future legislative changes remain outside the estimate. Legally fixed thresholds stay nominal; annually updated rules stay at the loaded value until an enacted update is available. |
| ACA / MAGI | 2026 HHS poverty guidelines, ACA dependents, MAGI room, and projected cap growth from the loaded FPL tables. | Marketplace premium quotes, plan-specific subsidies, and future ACA law changes are not predicted. |
| IRMAA | Roth Lab uses the loaded 2026 first-tier Medicare IRMAA threshold and the selected threshold-growth assumption. | Future CMS thresholds, all surcharge tiers, and household-specific Medicare billing details may differ. |
| Future-law risk | Scenario Lab can stress broad ordinary, capital-gains/dividend, and state tax rates by selected percentage points. | This is a simple rate-increase test. It does not try to guess future tax rules or rebuild the tax code. |
Validation
SimuPlan's calculations are tested because users should be able to trust that the model behaves consistently. Testing helps make sure formulas, projections, saved plans, imports, scenarios, and reports continue working as expected when the app changes.
SimuPlan includes focused tests for the core planning engine: projections, balance tracking, taxes, scenarios, simulations, and supporting calculations. These tests help catch formula changes or data-handling issues before they affect results.
Some SimuPlan outputs are compared against external calculators, historical datasets, and reference examples. These checks help confirm that results are reasonable and that any differences can be explained.
Automated browser tests open SimuPlan like a user would. They load sample plans, move through pages, edit settings, run workflows, and confirm that important screens render and save correctly. Basic anonymous analytics also help identify which pages and entry points need attention; those events do not include plan values, account names, balances, addresses, login credentials, or saved-plan contents.
SimuPlan is tested against different plan types, including struggling, middle, and strong plans, as well as Planning for Retirement and Household Retired Now modes. This helps catch changes that accidentally break important pages or planning states.
Interpretation
SimuPlan is built to help you understand retirement planning choices, compare scenarios, and see which assumptions matter most. Some decisions still deserve review from a planner, CPA, attorney, or Social Security specialist.
Help improve SimuPlan
Send a bug report, feature request, question, or general feedback directly from the app. SimuPlan includes only limited technical context automatically; you control whether to add a screenshot.