Will your retirement savings last?
Enter a few numbers and see how your plan holds up across 1,000 possible market futures - good years and bad, taxes and inflation included, in today's money.
- Free, no account needed
- A clear answer in seconds, in plain words
- Runs in your browser
Try it with your numbers
An example plan is filled in - change anything.
Opens the free simulator with these numbers filled in - check them and run it. Nothing is stored unless you create an account and save.
From your numbers to a clear answer
- 1
Enter your numbers
Your age, what you have saved, what you save each month, and what you plan to spend. About two minutes.
- 2
See how likely your money lasts
1,000 possible market futures, good and bad, summed up in plain words and in today's money.
- 3
Try changes
Save a bit more, retire a bit later, spend a bit less - and watch the answer move.
Example plan
Success rate
85%
We ran 1,000 possible futures for this plan. The savings last to age 90 in about 850 of them.
Chance the money runs out
Improve this plan
~85% → ~96%
Same example plan, with all three changes
Market outlook
Same example plan, three sets of assumptions
Cautious
56%
Stocks 6% · bonds 3%
Balanced
85%
Stocks 8% · bonds 4.5%
Historical
92%
Stocks 11.9% · bonds 4.8%
Success rate for each outlook - Balanced is the default
Your savings over time
Same example plan, in today's money
More realistic than a basic calculator
A basic calculator assumes the same return every year. Real retirements aren't that smooth.
Bad years are part of the plan
Every run mixes weak and strong markets instead of a steady average, and shows how often the money runs out - and when.
How the simulation worksTaxes and inflation included
Your spending is after tax, pensions and Social Security can rise with inflation, and every result is shown in today's money.
What's includedSpending that adapts
Spend a little less after bad years and more after good ones, or less later in life - and see what you would actually get to spend.
The spending strategiesStress tests
A crash right after you retire, a burst of inflation, surprise expenses, and markets with more extreme years than a bell curve.
About stress testsChecked against real history
Would your plan have survived 1929, the 1970s, or 2008? Step through every US market period since 1928.
The historical stress testFree to use. Pro when you want to go deeper.
Free
- The simulator, no account needed
- 1,000 simulated futures per run
- Improve: save more, retire later, spend less
- Free account: save 2 plans and compare them
Pro PRO
$29/year or $79 once
- 50,000 futures per run, for a more precise answer
- Spending that adapts to markets, and spending by age
- Stress tests and the historical stress test
- PDF report and 10 saved plans
How we check ourselves
A well-known study (the Trinity study) found that spending 4% of a 50/50 stock and bond portfolio, raised with inflation, lasted 30 years in about 95% of US historical periods. Our historical engine gets the same answer: 95.7% of the 30-year periods since 1928.
How the engine worksYour numbers stay with you. The simulation runs in your browser, and without an account your plan is kept only there. You never connect a bank account.
Frequently Asked Questions
- Is it free, and do I need an account?
- It's free, with no account needed: run the simulator and see your result for as long as you like. Create a free account only when you want to save plans and compare them. Pro, for $29/year or $79 once, adds more precision, flexible spending and stress tests - see Pricing for the details.
- What does "lasts in 850 of 1,000 futures" mean?
- Each run plays out your retirement in 1,000 possible market futures (50,000 on Pro). Each future has a different mix of good and bad years. If your savings last to the end of your plan in 850 of them, your success rate is 85%; in the other 150 the money runs out earlier. You also see what a bad case would leave you with, and at what age money tends to run out when it does.
- Are my numbers stored?
- The simulation runs in your browser. Without an account, your plan is kept only in that browser. If you create an account and save a plan, it is stored in your account so you can open it again.
- How is this different from a simple retirement calculator?
- A simple calculator assumes the same return every year. Real markets are uneven, and bad years early in retirement do the most damage. Retirement Lab shows the whole range of outcomes, includes taxes and inflation, and lets you test changes in seconds.