Retirement simulator

Monte Carlo your retirement plan

Enter your current invested balance, retirement age, savings contributions, retirement spending targets, and return assumptions. This page projects your likely net worth at retirement first, then stress-tests whether that retirement balance can support your spending over time.

Starting point

Define where the plan starts and how retirement timing should be evaluated.

Current retirement assets

List the accounts and cash buckets that make up your starting balance. The simulator sums them into invested net worth.

AmountAsset typeAction
Total retirement assets
$0
Bridge-accessible assets
$0
Pre-tax retirement assets
$0
Roth assets
$0
Cash
$0
Excluded / future assets
$0

Saving while working

Capture how much new money is still being added before retirement starts. Budget 401(k) withholding can seed the 401(k) contribution field here until you override it.

Spending targets

Set the retirement spending tiers the simulator can move between over time.

Advanced

Taxes and market assumptions

Configure tax drag, return assumptions, and inflation behavior.

One-time cash flows

Model uncertain inflows such as inheritances, severance, or future lump sums.

Spending behavior

Control spending-smile assumptions, inflation behavior after losses, and cash reserves.

Housing offsets

Model mortgage payoff relief that can reduce withdrawals later in retirement.

Mortgages

Retirement mortgage assumptions table
Mortgage Years remaining Monthly P&IAction

Social Security & pension offsets

Model claim timing and guaranteed income that can reduce portfolio withdrawals later.

This lets you model concerns that benefits could be reduced or unavailable by claim age. Monte Carlo paths receive the full benefit in some scenarios, then fall back to the reduced-benefit percentage when full benefits are not paid.

Retirement healthcare

Compare bridge coverage paths before Medicare and ongoing Medicare-era assumptions.

Bridge coverage path

Choose one bridge coverage path here. Medicare stays separate because it starts after the pre-Medicare bridge window.

Simulation controls

Control run depth and use an optional seed for repeatable comparisons.

Savings contributions and spending targets begin in today's dollars, then inflate path-by-path into nominal dollars. Expected nominal return is treated as an arithmetic average annual return, not a CAGR. The market model uses seedable stochastic nominal returns with negative years, Student-t fat tails, sequence risk, stochastic inflation, and explicit guardrail spending thresholds.

Mortgage P&I

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Mortgage Paid Off Around

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Social Security Starts Around

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Annual Social Security

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Retirement spending is assumed to already include active mortgage payments. As each mortgage pays off, the model reduces withdrawals by that row's monthly principal-and-interest amount, while Social Security reduces withdrawals once claimed. One-time payments are modeled as future cash inflows, treated as today's dollars inflated to the receipt year, included path-by-path using the configured probability, and can arrive earlier or later when timing variability is non-zero. The spending smile applies age-based multipliers to all three spend tiers before guardrails are chosen. Cash buffer is carved out of invested net worth into spendable cash, so it can still be used after risky investments hit $0.

Healthcare comparisons are modeled as planning assumptions only. They show estimated premium plus out-of-pocket ranges for pre-Medicare and Medicare-era coverage options so you can compare likely withdrawal pressure, not choose a specific plan.

Historical market replay

Historical replay uses one selected start year as the return and inflation path for the standard simulation output.

Populate the start year from a notable market window:

Children and dependents

No child/dependent assumptions saved yet.

Add one row per child or dependent, then add cost phases for expenses that start and stop at specific ages.

Scenario management

Scenario management

Saved retirement scenarios table
Saved scenariosSuccessMedian at retireRetirement ageGetting byNormalLife you wantExtraUpdated
No retirement scenarios saved yet.
Ready. The simulation compounds seedable stochastic annual return and inflation shocks, projects the retirement balance, then compares flexible guardrails, fixed spending cases, and named stress scenarios through age 100.