The 4% rule: what it is, where it comes from, and when to bend it
By the Fire Finance team · Updated September 25, 2026 · 6 min read
Key takeaway
Withdraw 4% of your starting portfolio in year one, then adjust that amount for inflation annually. Historically this survived nearly every 30-year period. For 40–50 year early retirements, 3–3.5% is the safer planning number.
The 4% rule is the engine inside almost every FIRE calculation: it converts “a pile of money” into “an income for life”. Withdraw 4% of your portfolio in the first year of retirement, then increase the withdrawal with inflation each year — and history says a balanced portfolio survives 30 years almost every time.
Where it comes from
Financial planner William Bengen tested withdrawal rates against every US retirement year since 1926 and found 4% survived even the worst sequences (retiring into 1929 or the 1970s stagflation). The 1998 Trinity Study confirmed it across stock/bond mixes: at 4%, a portfolio of at least 50% stocks succeeded in ~95%+ of historical 30-year periods.
What it implies
| Withdrawal rate | Corpus needed | Planning stance |
|---|---|---|
| 4% | 25× annual expenses | Standard 30-year retirement |
| 3.5% | ~29× annual expenses | Early retirees (40+ year horizon) |
| 3% | ~33× annual expenses | Very conservative / high-inflation contexts |
The honest caveats
- It is US-history-shaped. Other markets and future decades can differ. Treat 4% as a reference point and stress-test with lower rates.
- 30 years ≠ 50 years. Retire at 40 and you need the money to last much longer than the studies measured — hence 3–3.5% for early retirees.
- Sequence risk dominates. Average returns matter less than the order they arrive in. Two retirees with identical average returns can end up in completely different places if one hits a crash in year one.
- Rigid rules are strawmen. Real people spend less in bad years. Even small flexibility dramatically improves survival odds.
Using it in practice
Size your target with the 25× rule, then sanity-check the plan in the FIRE calculator — it lets you set your own post-retirement return and inflation, so you can see how a 3.5%-style plan changes the SIP you need today. Pro users can go further and simulate the withdrawal years directly in the Retirement Income Simulator.
Frequently asked questions
Is the 4% rule guaranteed to work?
No. It is a historical observation, not a law of nature — it summarises how a diversified portfolio behaved across past 30-year periods, mostly using US market data. It is an excellent planning anchor, not a promise.
Does the 4% rule work in India?
The research used US returns and US inflation. India has higher inflation but historically higher equity returns; many Indian planners use 3–3.5% for safety, or keep the 4% rule but with a corpus of 30× expenses. Conservative inputs beat clever ones here.
What if the market crashes right after I retire?
That is sequence-of-returns risk — the biggest threat to any withdrawal plan. Common defences: hold 2–3 years of expenses in debt/cash so you never sell equity in a crash, and stay flexible about spending in bad years.
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Educational content, not financial advice. Projections use the assumptions shown and are estimates — actual investment returns vary. Consult a registered advisor for personal decisions.