How Long Will Your Money Last Using the 4% Rule?

Thirty years. That's the short answer to how long your money will last using the 4% rule. The rule was designed so a retirement portfolio would survive about three decades of inflation-adjusted withdrawals (SmartAsset). But "about 30 years" is an average taken from many possible outcomes. Some retirees using the rule ended up with more money than they started with. A few ran close to zero. Where you land depends on things the rule doesn't know about you.

This guide covers where the 30-year figure comes from, what "success" actually means, why today's researchers disagree about the safe number, and how the answer shifts if you retire earlier or live longer.

The short answer: about 30 years

Here's how the rule works:

1. Year one: withdraw 4% of your starting portfolio.
2. Every year after: take the same dollar amount, raised for inflation. You don't recalculate 4% of whatever the balance is now.
3. Expect it to last: roughly 30 years, based on historical market returns.

Worked example. You retire with $1,000,000. In year one you withdraw $40,000. If inflation runs 3% that year, you withdraw $41,200 in year two, and so on. You don't cut back when markets fall or spend more when they rise.

Quick sanity check: $1,000,000 divided by $40,000 is 25. If your investments only kept pace with inflation and earned nothing more, the money would run out in year 25. The rule assumes your portfolio earns enough above inflation to stretch those 25 years to 30. Market returns cover that gap, and that's where the uncertainty comes in.

Where the 30-year figure comes from

Two studies set the benchmark.

Bengen, 1994. Financial planner William Bengen tested withdrawal rates against every rolling 30-year period of U.S. market history going back to 1926. He called a rate "safe" if it never ran out of money in any of those periods, including the worst ones. About 4% passed (Wikipedia, William Bengen).

The Trinity study, 1998. Three professors tested rolling periods of 15 to 30 years from 1926 to 1995. A 4% withdrawal from a 50/50 or 75/25 stock/bond portfolio succeeded in roughly 95–100% of 30-year periods (Wikipedia, 4% rule).

Both studies looked backward. They asked what would have worked in the past, not what will work for someone retiring today.

How long will money last using the 4% rule? It depends on what "last" means

Most articles leave out how these studies scored the results.

In the Trinity framework, a retirement counts as a success if the portfolio hasn't hit zero by the end of the period. That's the whole test. Someone who finishes 30 years with almost nothing left scores the same as someone whose portfolio tripled (The Poor Swiss, Trinity Study).

That matters for your plan in two ways:

• "Lasts 30 years" doesn't mean "lasts comfortably." In some successful outcomes, the last few years of retirement were running on fumes.
• The answer is a range of years. Across historical periods, 4% withdrawals often lasted well beyond 30 years, and some left large balances behind. In the bad periods, the money barely made it.

So a better version of the question is: what are the odds my money lasts as long as I do? A probability answers that better than a single number of years.

Why two retirees using 4% get different results

Picture two people. Same savings, same 4% withdrawal, same average market return over 30 years. One retires into a bull market and the other into a crash.

They can still end up in very different places. This is called sequence-of-returns risk. When markets fall early in retirement, you're selling investments at low prices to pay your bills. Those shares are gone and can't recover when the market does. A bad stretch in year two hurts far more than the same stretch in year twenty-two.

For this reason, projecting with a single average return can mislead you. An average hides the order of returns, and for a retiree the order is what decides the outcome (Kitces).

A Monte Carlo simulation deals with this directly. In plain terms, it runs your plan through hundreds or thousands of possible market paths, some good early, some bad early, some mixed. Then it counts how many of those paths keep you funded to the end. The result is a success rate, such as "your money lasted in 870 of 1,000 futures."

Today's numbers: 3.9%, 4.7%, and why they disagree

The 4% figure is more than 30 years old. Researchers still update it, and they don't agree.

Sources: Wikipedia, William Bengen; Morningstar, The State of Retirement Income 2025, Dec 2025; Morningstar, safe withdrawal rate for 2026.

Why the gap? The methods ask different questions:

• Bengen looks backward. His newer 4.7% figure comes from a more diversified portfolio tested against history.
• Morningstar looks forward. It uses its own forecasts of future stock and bond returns and inflation. It calls a rate safe if money is still there in 90% of simulated outcomes. Its model portfolios hold roughly 30–50% in stocks. Morningstar's figure rose to 3.9% from an earlier 3.7% (TheStreet).

Neither number is "right." They show the 4% rule sitting in the middle of a reasonable range, not on a fixed line.

Retiring early? A longer retirement needs a lower rate

The 4% rule was built for 30 years. If you retire at 65 and plan to age 95, that fits. If you retire at 60 or 55, it doesn't.

Morningstar's early-retirement research puts some numbers on it. For a portfolio with 50% in stocks:

Source: Morningstar, What Is a Safe Withdrawal Rate for Early Retirement?

An independent update of the Trinity study, using U.S. data from 1871 through 2025, reached a similar conclusion. It found 4% still holds for 30 years but is no longer reliably safe over longer horizons. Even an all-stock portfolio had only about an 85% success rate at 4.5% (The Poor Swiss, Updated Trinity Study).

What about withdrawing more than 4%? Success rates drop quickly above 4%. Published tables don't agree on how quickly, because they use different time periods, portfolios and definitions of success (White Coat Investor). Rather than trusting one table, test the rate you're considering against your own numbers.

Three risks the rule doesn't account for

The 4% rule only tracks your withdrawals and the market. Three other things can shorten how long your money lasts.

1. Living longer than you planned

About one in three 65-year-olds may live to at least 90, according to the Social Security Administration (Retirement Information for Medicare Beneficiaries, 2026). A plan that ends at 85 is effectively betting against a third of retirees. If you retire at 65 and live to 95, you need the full 30 years the rule was built for, and possibly more.

2. Health care costs

Fidelity estimates a 65-year-old retiring in 2025 will spend $172,500 on Medicare premiums, deductibles and prescriptions over retirement. That figure doesn't include long-term care (Fidelity Investments, 2025 Retiree Health Care Cost Estimate, Jul 2025). Medicare costs can also rise with income-based surcharges. If your spending estimate doesn't include these costs, your withdrawal rate is higher than you think.

3. Rigid spending

The classic rule assumes you never adjust. Real retirees do. Some planners argue for flexible approaches, such as cutting back a little after a bad year or spending more after a strong one, instead of a fixed inflation-adjusted withdrawal (Retirement Researcher). Being willing to adjust is one of the main things you control.

Does the 4% rule fit your plan?

The rule gives you a reasonable starting point. To see how it applies to you, check:

• How many years you need to fund. Count from your retirement age to at least 95.
• Your real withdrawal rate. Divide your annual spending, including health care, by your savings.
• Your allocation. The studies assume a specific stock/bond mix, and yours may differ.
• Your flexibility. Can you cut spending for a year if markets fall early?

Doing this matters. EBRI's 2025 Retirement Confidence Survey found only 52% of workers have estimated the monthly income they'll need in retirement (EBRI/Greenwald, Retirement Confidence Survey 2025, Fact Sheet 3). The rest are guessing.

See how long your own money lasts

The 4% rule answers the question for a typical retiree in a typical market. Your plan needs an answer for you.

That's what we built Monte Climb's retirement calculator to do. Enter three numbers: your age, your retirement savings and your monthly spending. We run them through 1,000 simulated futures and show you how many stay funded. Plans run to age 95 by default, and you can push them further. Everything runs in your browser, and nothing is saved until you choose to save it.

If the result raises more questions, like Can I retire at 62? or What can I sustainably spend?, you can ask William, our AI planner, who shows his work.

Your result is a probability, not a promise. It's also planning software, not financial advice. But it's built on your numbers instead of an average.

Show my answer →

Frequently asked questions

How long will $1 million last using the 4% rule?

About 30 years. Under the 4% rule you withdraw $40,000 in year one and raise that amount with inflation each year after. Historically this lasted roughly three decades in most market conditions, though results ranged from portfolios that grew to ones that came close to zero.

Is the 4% rule still safe in 2026?

For a 30-year retirement it's still in a reasonable range, but estimates differ. Morningstar's forward-looking research puts the safe starting rate at 3.9% for 90% success over 30 years. William Bengen's 2025 historical analysis, using a more diversified portfolio, puts it at 4.7%.

What withdrawal rate should I use if I retire early?

Lower than 4%. For a portfolio with 50% in stocks, Morningstar's research suggests about 3.5% for a 35-year retirement and 3.2% for a 40-year retirement.

What does 'success' mean in the 4% rule studies?

In studies like the Trinity study, a retirement counts as a success if the portfolio hasn't run out of money by the end of the period. Ending with almost nothing left counts as a success, the same as ending with a large balance.

Why do two people using the 4% rule get different results?

Because of sequence-of-returns risk. If markets fall early in retirement, you sell investments at low prices to cover spending, and those losses are hard to recover. Two retirees with the same average return can end up in very different places depending on the order of their returns.