The 4% rule is the best-known guideline in retirement planning. It says that in your first year of retirement you can withdraw 4% of your portfolio, then adjust that amount for inflation each year, with a reasonable chance the money lasts about 30 years. It is the bridge between "how big is my pot" and "how much can it pay me."
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How the 4% rule works
Imagine you retire with $1,000,000. Four percent of that is $40,000 — your spending budget for year one. Each following year you raise that figure by inflation to keep your purchasing power steady. The idea is that a sensibly diversified portfolio can sustain those withdrawals through most historical market conditions without running dry.
Flip it around and you get the famous corollary: to cover a given level of spending, you need 25 times your annual expenses (because 1 ÷ 0.04 = 25).
| Annual spending | Portfolio needed (25×) |
|---|---|
| $40,000 | $1,000,000 |
| $60,000 | $1,500,000 |
| $80,000 | $2,000,000 |
Where it came from
The rule traces back to research in the 1990s — financial adviser William Bengen's analysis of historical returns, later reinforced by the well-known "Trinity study." Both looked at how various withdrawal rates would have survived past market conditions, and 4% emerged as a rate that held up across most 30-year windows, including ones containing serious downturns.
Does it still work?
It remains a reasonable planning anchor, but it is not a guarantee, and it has real critics. Three concerns come up most:
- Sequence-of-returns risk. A bad run of markets in your first few retirement years is far more damaging than the same run later, because you are withdrawing from a shrinking pot.
- Longer retirements. The original work targeted about 30 years. Retire very early, and the money may need to last 40–50 years, which strains the rate.
- Lower expected returns. In periods of low yields, some planners prefer a more cautious 3% to 3.5%, accepting that it requires a larger portfolio.
Many retirees also stay flexible — trimming spending in down years — which makes the rule more robust in practice than a rigid formula suggests.
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How to use it
Treat the 4% rule as a target to aim at, not a precise promise. Multiply your expected annual spending by 25 to get a goal, then use a calculator to see whether your current saving puts you on track to reach it. As you near retirement, revisit the rate in light of your time horizon and the markets.
The bottom line
The 4% rule turns a portfolio into an income estimate: spend 4% in year one, adjust for inflation, and aim for 25 times your annual expenses. It is a sound starting point, but treat it as a flexible guideline — adjust for very early retirement, weak markets, and your own comfort with risk.
Project your nest egg and its income
Free and private — model your savings and the income they could pay.
Frequently asked questions
Is the 4% rule safe?
It is a reasonable planning anchor drawn from historical market studies, designed for roughly a 30-year retirement. It is not guaranteed — very long retirements, weak early returns, and high fees can all strain it, which is why some people choose a more conservative 3% to 3.5%.
4% of what, exactly?
Four percent of your total invested portfolio value at the moment you retire. That gives your first-year withdrawal; in later years you adjust that dollar amount for inflation rather than recalculating 4% of the new balance.
Does the 4% rule account for inflation?
Yes. You take 4% in the first year, then increase that withdrawal each year by inflation so your purchasing power stays roughly constant. The underlying studies tested the rule on an inflation-adjusted basis.
Should I use 3% or 4%?
4% suits a roughly 30-year horizon. If you are retiring early and need the money to last much longer, or you want extra safety, 3% to 3.5% is more conservative — but it requires a larger portfolio to support the same spending.