The 4% rule was designed for a 30-year retirement, and for that horizon it held up in almost every historical period. For a 40- or 50-year early retirement, a rigid 4% withdrawal (raised every year for inflation, no matter what) fails more often. Much of the research on long horizons points to a starting rate closer to 3.25% to 3.5%, or to keeping 4% but committing to cut spending in bad markets. Which one fits depends on how flexible your budget is.
Here’s what the 4% rule actually says, why longer retirements strain it, and the adjustments that make it workable. This is educational; your own plan deserves its own stress test.
What the 4% rule actually says #
In 1994, financial planner William Bengen tested withdrawal rates against U.S. market history back to 1926. He looked for the highest first-year withdrawal, raised each year by inflation, that never ran a portfolio of 50% to 75% stocks (with the rest in intermediate Treasury bonds) out of money in any 30-year period. The answer was about 4%. The 1998 “Trinity study” by three Trinity University professors reached similar conclusions using success rates.
Three details get lost in the retelling:
- It’s a first-year rate. You withdraw 4% of your starting balance, then the same dollar amount adjusted for inflation every year, whatever the market does.
- It was a worst case, not an average. In most historical periods, retirees could have spent more and still died wealthy.
- It assumed 30 years, no fees and no taxes.
The FIRE version, “save 25 times your spending,” is just 4% flipped around.
Why a 40-year retirement strains a fixed 4% #
Sequence of returns risk #
Early losses do the most damage, because you’re selling shares at low prices to cover spending, and those shares aren’t there for the recovery. Here’s an actual example using S&P 500 total returns from NYU Stern’s data. A $1,000,000 all-stock portfolio withdrawing $40,000 in the first year, raised 3% a year, starting in 2000, ran out of money in year 24. That’s despite the market averaging 8% a year over 2000 to 2025. Run the same returns in reverse order and the portfolio ends with about $4.4 million. All-stock is more aggressive than Bengen’s mix, but the lesson carries over: a bad first decade can sink a fixed plan.
More time for bad decades to show up #
A longer retirement has more room for a lost decade, an inflation spike and a slow recovery. Using NYU Stern returns and CPI data, the worst 30-year stretch for U.S. stocks after inflation since 1928 returned about 4.3% a year (1965 to 1994). The worst 40-year stretch returned about 4.1% (1969 to 2008). Averages hold up over long periods. But over those periods you’re withdrawing every year, and the order of returns decides whether a fixed withdrawal survives.
Inflation compounds your withdrawals #
A fixed rule raises spending with inflation every year. A few years of 6% to 8% inflation early in retirement, like the 1970s or 2021 to 2023, permanently lifts your withdrawal path. If returns don’t keep up in those same years, your withdrawal rate on the shrunken portfolio climbs fast.
What withdrawal rate is safer for 40 or 50 years? #
Research on long horizons tends to land in these ranges. Treat them as rules of thumb, not guarantees:
| Retirement length | Commonly cited starting rate for a fixed, inflation-adjusted plan | FIRE multiple (spending ×) |
|---|---|---|
| 30 years | about 4% | 25 |
| 40 years | about 3.5% | about 28.6 |
| 50 to 60 years | about 3.25% to 3.5% | about 28.6 to 30.8 |
Karsten Jeske’s long-running safe withdrawal rate series at Early Retirement Now is the most detailed public work on 50- and 60-year horizons. It finds the historically fail-safe rate falls with longer horizons and with high stock valuations at the start, and it usually lands in that 3.25% to 3.5% band. Bengen later raised his own estimate using a broader mix of stocks, which is a reminder that these numbers depend on assumptions.
What that means in dollars, on a $1,500,000 portfolio:
- 4% → $60,000 in year one
- 3.5% → $52,500
- 3.25% → $48,750
That $7,500 to $11,250 a year is the price of not having to adjust. Most early retirees can adjust, which is why flexible methods are popular.
Four ways to keep a higher withdrawal rate safely #
1. Guardrails #
The Guyton-Klinger guardrails method, from planner Jonathan Guyton and William Klinger, sets two rules. If your current withdrawal rate rises more than 20% above your starting rate (because the portfolio fell), cut spending by 10%. If it falls more than 20% below (because the portfolio grew), raise spending by 10%. That small flexibility supports a higher starting rate than a rigid plan.
2. Variable percentage withdrawal #
Withdraw a percentage of the current balance that rises with age, so spending tracks the portfolio and you can’t run out. Our guide to variable percentage withdrawal walks through it.
3. A cash or bond buffer for the first years #
Holding one to three years of spending in cash or short-term bonds lets you avoid selling stocks right after a crash. It doesn’t fix a truly bad decade, but it helps in the most common scenario, a sharp drop followed by a recovery. See how much cash to keep in early retirement.
4. A little income in the early years #
Even $15,000 to $20,000 a year of part-time or freelance income in the first five to ten years sharply reduces how much you sell during a downturn. It works on the exact years sequence risk targets. It’s the core idea behind Barista FIRE.
Don’t forget taxes, fees and allocation #
- Fees come off the top. A 1% advisory fee turns a 4% plan into effectively 5%.
- Taxes are part of spending. If most of your money is in traditional 401(k)s and IRAs, your withdrawal has to cover the tax too.
- Stock share matters. Bengen’s research found 50% to 75% stocks worked best. Too little stock can fail slowly over 40 years because growth doesn’t keep up with inflation.
Test your own numbers #
Rules of thumb are a starting point. Test your plan against real history and randomized paths with a FIRE retirement simulation, and read up on sequence of returns risk.
Retire Goals handles two quick pieces. Its FIRE Number calculator divides your annual spending by any withdrawal rate you choose, so you can see your target at 4%, 3.5% and 3.25% in seconds. The Will My Money Last calculator takes a portfolio, first-year spending and an expected return, and simulates the drawdown month by month with yearly inflation raises. It shows how many years the money covers and the spending that would last thirty. For a 40- or 50-year plan, look at the years-covered figure rather than the thirty-year amount, and use a conservative return.
Frequently asked questions #
Does the 4% rule include taxes and investment fees? #
No. The original research ignored both. Subtract any advisory or fund fees from your withdrawal rate, and make sure your withdrawal covers the income tax on money coming out of traditional accounts.
What withdrawal rate is safe for a 50-year retirement? #
For a fixed, inflation-adjusted plan with no spending cuts, much of the research points to about 3.25% to 3.5%. If you’re willing to use guardrails or cut spending after big drops, starting closer to 4% can work.
Does the 4% rule work if I retire into a crash? #
A rigid 4% plan is most at risk exactly then. Skipping inflation raises, cutting discretionary spending, drawing from a cash buffer, or earning some income for a few years all reduce the damage.
Is 4% too conservative for a traditional 30-year retirement? #
Often, yes. In most historical 30-year periods, a 4% starting rate left retirees with more money than they started with. It was designed for the worst periods, so retirees with flexible budgets or income like Social Security and pensions may be able to spend more.