Monte Carlo Retirement Calculator
See how often your savings cover your yearly spending across 5,000 simulated markets. Free, no sign-up.
Savings over time, today's dollars
Illustrative estimate, not a forecast or advice. It leaves out taxes by account type, Social Security timing and required withdrawals.
How this calculator works
- It runs 5,000 retirements, each with its own sequence of yearly market returns.
- Each year your spending, raised for inflation, comes out first. The rest earns that year's return.
- A retirement lasts when savings cover every year's spending. The headline is the share that do.
- Returns use the same market assumptions as a full Praxion plan, for the mix you pick:
| Asset | Growth after inflation, first 10 years | Long-run growth after inflation | Yearly swing (volatility) |
|---|---|---|---|
| stocks | 3.4% | 4.0% | 18% |
| bonds | 2.3% | 2.1% | 6% |
| cash | 0.9% | 0.6% | 1% |
Compound yearly growth after inflation, before fees. Moves from the first-10-year figures to the long-run figures over the next 10 years. Spending rises 3% a year. Fund fees: 0.25% a year. Our methodology page shows the same forecasts before inflation.
How to read your result
- The percentage is a share of simulated markets, not a promise. Real markets can be better or worse.
- The poor-market line shows timing risk. Weak returns early in retirement do the most damage. See sequence of returns risk.
- To raise the result, try lower spending, more savings or a shorter retirement, and compare.
What this calculator leaves out
- Taxes that differ by account type (401(k), IRA, Roth, brokerage)
- When you claim Social Security and how it is taxed
- Required minimum distributions and Roth conversions
- Spending that changes as you age, and one-off costs such as health care
- Inflation that changes year to year, rare extra-severe market years, and changing your mix over time
A free Praxion plan models these with your own accounts and runs the same kind of simulation on the whole plan.
Frequently asked questions
What is a Monte Carlo retirement calculator?
It tests your retirement plan against many possible market paths instead of one average return, and reports how often your savings last.
What result should I aim for?
There is no single right number. Higher means savings lasted in more simulated markets. A low result is a sign to revisit spending or savings; a very high one can mean you could spend more.
Why can a more aggressive mix give a lower result?
The forecasts used here expect stocks to earn only modestly more than bonds while swinging far more from year to year. More stock widens the range of outcomes, so more poor-market paths run out. With higher stock-return forecasts the order can change, so this is not a pick of mix.
Is this the same as the 4% rule?
No. The 4% rule is a rule of thumb from past markets. This calculator tests your own withdrawal amount across many simulated markets using current return forecasts.
Does it include Social Security?
Not directly. Enter only the spending Social Security and pensions don't cover. A free Praxion plan models claiming age and taxes.
Related reading
Test your whole plan
Add Social Security, taxes and each account. Praxion runs the simulation on your full plan.
Start your free planPraxion Finance is a decision-support tool, not a registered investment adviser.