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Free tool · runs on your device · updated October 11, 2026

How Long Will My Money Last? Retirement Calculator

How long your money lasts depends on what you spend, what income you have, and the markets you happen to retire into, which nobody can know ahead of time. So this calculator doesn't guess one return. It runs your plan through every stretch of real U.S. market history since 1928, from the 1929 crash to 2008, and shows how often your savings lasted, how long they lasted in the worst years, and what was typically left.

Your figures never leave this page. All 98 years of market data are built into the page, so the calculation happens on your device and nothing is sent anywhere. That stays true if you sign up for the free kit below: it sends only your name and email.

Each box starts with example numbers. Swap in yours and the results recalculate as you type.

You and your savings
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IRAs, 401(k)s, brokerage accounts and savings. Leave out your home and an emergency fund you won't touch.

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Everything you spend in a month, plus the income tax you'll owe on withdrawals. Money from a traditional IRA or 401(k) is taxed when it comes out.

Income that pays part of the bills
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Both of you together if married. Not sure what it will be at each age? The break-even calculator works it out.

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Social Security rises with inflation every year, so the calculator keeps it level in today's dollars. A pension without a raise loses buying power each year, by however much prices actually rose in each stretch of history.

How the money is invested

Stocks are the S&P 500 with dividends reinvested; bonds are 10-year U.S. Treasuries. The mix is reset to your chosen split every year.

How long your money lasts

Results appear here.

Keep your plan, and get the free Retirement Gap Kit

Your private plan link

This link reopens this page with your numbers filled in. Your figures sit after the # mark, a part of the address browsers never send to any website, so they stay on your device. Bookmark it or save it in your notes. Anyone you give it to can see your numbers.

The Retirement Gap Kit, by email

Five short emails from me, Rob Fore, over about ten days. Each one walks through one of the free calculators: when to claim Social Security, Medicare's income surcharge, taxes on your benefits, and benefits for spouses and widows. No sales pitches. Unsubscribe any time.

Only your first name and email are sent, to systeme.io, which sends the emails. Your calculator figures are not. Privacy notice.

Why one answer is the wrong answer

Most retirement calculators ask for one average return, say 6%, and print the age your money runs out. Markets don't pay an average. They pay 1931 and 1933, 1974 and 1975, 2008 and 2009, and the order matters. A crash in your first few years of withdrawals does far more damage than the same crash 20 years in, because you're selling to live while prices are down, and that money never gets the recovery.

So this calculator replays history instead. With a 30-year plan it starts you in 1928 and runs 30 real years, then starts you in 1929, and so on: 69 different retirements. Each one uses that era's actual stock returns, bond returns and inflation, in the order they happened.

What the history says about the 4% rule

In 1994 a financial planner named William Bengen ran this same test and found that a retiree with half stocks and half bonds could have taken about 4% of savings in the first year, then raised it with inflation, and never run out over 30 years. That became the "4% rule". His worst year to retire was 1966: a decade of poor returns combined with the high inflation of the 1970s.

This calculator gets the same worst year. Taking 4% of $1,000,000, that's $40,000 a year, with half in stocks and no fees, the money lasted 30 years in 64 of 69 periods. The ones that fell short started in 1964, 1965, 1966, 1968 and 1969, and the worst, starting in 1966, ran out at about age 89 of a planned 95. The amount that survived every period was 3.7% of savings, slightly under Bengen's figure because this calculator takes each year's money out at the start of the year and uses 10-year Treasuries, both more cautious than his setup.

The 4% rule is a worst-case finding, not a forecast. In a typical period the same retiree reached 95 with $1,069,938 left, in today's dollars, more than they started with.

How long will $500,000 last?

Take a 65-year-old with $500,000 who spends $4,000 a month, collects $2,200 a month of Social Security from 67, keeps half in stocks and pays 0.5% in fees. For the first two years they withdraw $48,000 a year, then $21,600 once Social Security starts. Across 69 periods since 1928, the money lasted to 95 in 44. The worst start, 1969, ran out at about age 82. Put your own numbers in the calculator to see your range.

The levers that move the answer most

  • Spending. Every $100 a month you don't need from savings is $1,200 a year for the rest of the plan. Spending is usually the biggest lever by far.
  • When Social Security starts. A later start means drawing more from savings for a few years, but a check up to 77% larger for life, and that larger check lowers every withdrawal after it. Try different start ages above.
  • Fees. One percent a year sounds small. For the 4% retiree above, a 1% yearly fee cut the periods that lasted 30 years from 64 to 55 of 69.
  • The stock share. With no stocks at all, the same 4% plan lasted in only 27 of 69 periods, because bonds alone have barely kept ahead of inflation. Very high stock shares swing harder in both directions.
  • Working a few more years, even part time, shortens the stretch that savings have to cover.

What this calculator leaves out

  • Spending that changes with age. Spending is held level in today's dollars. Many retirees spend less in their 80s, though health costs can rise.
  • Taxes in detail. Include your income tax in the spending figure. Roth, traditional and taxable accounts are taxed differently, and the order you draw them down matters.
  • Large one-time costs such as a new roof, a car or long-term care.
  • Adjusting as you go. Real retirees cut back after bad years. The calculator holds spending steady, so it is stricter than real life.
  • A future worse than the past. History since 1928 includes a depression, wars and high inflation, but it is one country's history. It is not a guarantee.

For the Social Security and Medicare pieces of the plan, see the other free calculators, including the IRMAA calculator for higher-income Medicare premiums.

Before you rely on it

This is arithmetic on historical data. It is not investment or financial advice, and I'm not a financial adviser. Past returns don't promise future ones. For a plan built around your accounts and taxes, a fee-only fiduciary planner is the kind of help that works for you rather than for a product.

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