The 4% rule is a rule of thumb for how much you can spend from your investments without running out. In its classic form: withdraw 4% of your portfolio in your first year of retirement, then increase that dollar amount with inflation every year after.
Flip it around and you get the most common way to estimate a FIRE number: multiply your yearly spending by 25, since 4% is one twenty-fifth.
Where it came from
In 1994, financial planner William Bengen tested withdrawal strategies against historical U.S. market returns going back to the 1920s. He looked for the highest starting withdrawal rate that would have lasted at least 30 years in every period he studied, including retirements that began just before the Great Depression or the high inflation of the 1970s. The answer was about 4%.
A few years later, three professors at Trinity University ran a similar analysis across different stock and bond mixes. Their 1998 paper, often called the Trinity Study, found that portfolios with a large share of stocks supported 4% withdrawals over 30 years in the vast majority of historical periods. Together, these studies made "4%" the default answer to "how much can I spend?"
How it works in practice
Say you retire with $1,000,000:
| Year | How it's set | Withdrawal |
|---|---|---|
| 1 | 4% of $1,000,000 | $40,000 |
| 2 | $40,000 + 3% inflation | $41,200 |
| 3 | $41,200 + 3% inflation | $42,436 |
The key detail is that year 2 and beyond are tied to inflation, not the market. If the market drops 20% in your first year, you still take $41,200. That's what makes the rule simple to follow, and it's also its biggest risk.
Why early retirees often use less than 4%
Longer retirements
The original research covered 30-year retirements, which fits someone retiring at 65. Retire at 40 and you might need your money for 50 years. Small differences compound over that extra time, so a slightly lower rate buys a lot of safety.
Sequence-of-returns risk
The order of returns matters as much as the average. A crash in your first few years of retirement, while you're also withdrawing, can do lasting damage, because you sell shares at low prices and they're not there for the recovery. Most historical failures of the 4% rule started with poor early returns.
Taxes and fees
The 4% is your total withdrawal. If part goes to taxes or a 1% advisory fee, less is left to spend.
What different rates mean for your target
Here's what a household spending $50,000 a year would need at different withdrawal rates:
| Withdrawal rate | Multiple of spending | Target for $50,000/yr |
|---|---|---|
| 4% | 25× | $1,250,000 |
| 3.5% | 28.6× | $1,428,571 |
| 3.25% | 30.8× | $1,538,462 |
| 3% | 33.3× | $1,666,667 |
Dropping from 4% to 3.5% raises the target by about 14%. For many people, that's only a few extra years of saving in exchange for a noticeably safer retirement.
Flexibility beats precision
The historical failures of the 4% rule assume you never adjust. Real retirees usually do. A few common approaches:
- Guardrails: cut spending by a set percentage when your portfolio falls well below its starting value, and allow raises when it grows well above.
- Skip inflation raises after bad years: keep your withdrawal flat instead of increasing it.
- Keep a little income: even a small amount of part-time work in the early years greatly reduces sequence-of-returns risk. That's the idea behind Barista FIRE.
- Count Social Security: benefits that start in your 60s reduce how much your portfolio has to cover later.
Treat 4% as a starting point for planning, not a guarantee. If your plan works at 3.5% and you stay flexible, you're on solid ground.
Common questions
Does the 4% rule mean I withdraw 4% every year?
No. You withdraw 4% of your starting balance in the first year, then raise that dollar amount by inflation each year, regardless of how the market did. Withdrawing a fixed 4% of whatever the balance is each year is a different strategy.
Is 4% safe for early retirement?
It was tested over 30-year retirements. For 40 to 50 years, many planners and FIRE followers prefer 3.25–3.5%, or stay at 4% but plan to cut spending in bad markets.
Does the 4% rule include taxes and fees?
No. The 4% covers your total withdrawal, so taxes and investment fees come out of it. That is why our calculator adds the tax on withdrawals to your FIRE number and why low-cost funds matter.
This guide is for education, not personal financial or tax advice. Examples use simplified assumptions, such as a steady 5% return after inflation, that real markets won’t follow. Tax figures are for the 2026 tax year.