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How long will my money last?

Enter your savings, the monthly withdrawal in today’s money, the return and inflation. The calculator shows when the money runs out, how much to withdraw to last as long as you want and compares it with the 4% rule.

Educational simulation. Not investment advice. Results are estimates based on the data you enter and do not replace advice from a qualified professional.

Reviewed on Nov 1, 2026

Example: $600,000 invested, withdrawing $3,000 a month adjusted for inflation, starting at 62.

Your savings
Time horizon

Withdrawals at the start of each month, raised with inflation. Use the return after taxes and fees.

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—Your money lasts
—

Balance over the years (today’s money)

Year-end balance with your withdrawal, with the withdrawal that lasts your chosen horizon and with the 4% rule.

Tap the chart to see the values.

How long it lasts at each withdrawal rate

Years until the money runs out, withdrawing 3% to 9% of the starting balance a year, at the same real return.

Tap the chart to see the values.

Year by year

Today’s money; the last column shows the monthly withdrawal in that year’s money, adjusted for inflation.

Next step

Take this page’s results to another calculator with the fields already filled in.

Stress-test with varying returns (Monte Carlo) →Plan for financial independence →

The summary lists your inputs, results, formulas, assumptions and sources. The full report also includes the charts and interpretations, in color. In the print dialog, choose Save as PDF.

Method, assumptions and sources

Formulas

Real return r = (1 + return) ÷ (1 + inflation) − 1; monthly rate i = (1 + r)^(1/12) − 1
Next month’s balance = (balance − withdrawal) × (1 + i), in today’s money, until the balance no longer covers the withdrawal
Withdrawal lasting n months = P × i ÷ [(1 + i) × (1 − (1 + i)^−n)] (withdrawals at the start of each month)
4% rule = 4% × P ÷ 12; perpetual withdrawal = P × i ÷ (1 + i)

Assumptions and limits

  • Constant return and inflation; withdrawals raised with inflation; values in today’s money. Use the return after taxes and fees. Social Security, pensions, health costs, estate goals and return variability are not included (see the Monte Carlo simulation).
  • The 4% rule comes from studies of historical U.S. data (Bengen, 1994; Cooley, Hubbard and Walz, 1998) and is cited as a reference, not a guarantee.

Official sources and references

Frequently asked questions

What is this calculator for?

It shows how long savings can pay a monthly withdrawal that rises with inflation, and how much you can withdraw for the money to last the number of years you choose. It works for retirement, a sabbatical or living off investments.

How do I read the example result?

With $600,000, a $3,000 monthly withdrawal and a 2.91% real return (6% return and 3% inflation), the money lasts 22 years and 7 months, to about age 84. To last 30 years, the withdrawal would be $2,483; to never touch principal, $1,434.

Why does the calculator use the real return?

Because the withdrawal rises with inflation every year to keep its buying power. Working in today’s money with the return above inflation gives the same result and is easier to read. The table also shows the withdrawal in each year’s money.

What is the 4% rule?

A guideline from U.S. research: withdrawing 4% of the portfolio in the first year and raising it with inflation lasted 30 years in most historical scenarios. In the example, it is $2,000 a month. It is not a guarantee, and low future returns or high fees can make it too aggressive.

What return should I use?

The expected average return of your portfolio after taxes and fees. Be prudent: a difference of 1 point a year changes the duration by several years. Many planners assume a real return of 2% to 4% for a balanced portfolio, but no one knows future returns.

Does it account for returns that vary?

No. Here the return is constant, and bad years right after withdrawals begin shorten the duration. Use the "Next step" button to take your numbers to the Monte Carlo simulation, which runs thousands of return sequences and shows the chance the money lasts.

When should I talk to a professional?

Before you retire, it is worth building the plan with a fee-only financial planner: taxes, Social Security timing, health care and estate plans change the math. This calculator is an educational simulation and does not include those factors.

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How long will my money last in retirement

Anyone living off savings has to answer one question: how much can I withdraw each month without running out too soon? The answer depends on three numbers: the size of the portfolio, the withdrawal and the return above inflation.

Think in today’s money

The calculator raises your withdrawal with inflation every year to keep its buying power. That is why the real return matters: with a 6% return and 3% inflation, the real return is 2.91%.

The example

With $600,000 and a $3,000 monthly withdrawal (6% of the portfolio a year), the money lasts 22 years and 7 months: starting at 62, it runs out at about 84. To last 30 years, the withdrawal would have to be $2,483 a month; to never touch principal, $1,434.

The 4% rule

Research by William Bengen (1994) and the Trinity study (1998) found that withdrawing 4% of the portfolio in the first year and raising it with inflation lasted 30 years in most historical U.S. scenarios. In the example, that is $2,000 a month. It is a guideline, not a guarantee.

Sequence risk

This calculation uses a constant return. In real life some years earn less, and losses right after withdrawals begin shorten the duration considerably. To measure that risk, take your numbers to the Monte Carlo simulation, which runs thousands of return sequences.