How Long Will Your 401k Last in Retirement?
- Projected balance (at retirement)
- US$1.846.072
- Investment growth
- US$1.366.123
How long your 401k lasts depends on the gap between what you withdraw and what your balance earns, adjusted for inflation. The 4% rule suggests a starting withdrawal of 4% of the balance, then rising with inflation, is likely to last about 30 years. On a $750,000 balance that is $30,000 in the first year, or about $2,500 a month; a more conservative 3% would draw $22,500. Higher withdrawals or poor early returns shorten that horizon. One important boundary is sequence-of-returns risk: a market downturn in your first retirement years, while you are withdrawing, does far more damage than the same downturn later, because you sell assets at low prices. Projections also ignore taxes, other income, and required minimum distributions from age 73, so treat any figure as an estimate rather than a guarantee.
Published · Last verified · Written and fact-checked by Ali Raza · Our methodology · Terms explained
What determines how long a 401k lasts?
How long a 401k lasts comes down to a simple tension: each year your balance earns a return, and each year you withdraw money to live on. If your withdrawals stay below what the balance earns, it can last indefinitely. If they exceed the earnings, the balance shrinks — faster every year as inflation lifts your withdrawals.
Inflation is the quiet driver. A withdrawal that covers your costs today must grow each year just to maintain your purchasing power, and at 3% inflation your cost of living roughly doubles in about 24 years. That rising need is often what eventually drains a portfolio.
What is the 4% rule?
The best-known guideline is the '4% rule': withdraw 4% of your balance in the first year of retirement, then adjust that dollar amount for inflation each year. Historically, this rate gave a high chance of a portfolio lasting about 30 years. On a $750,000 balance, that is $30,000 in year one, or about $2,500 a month.
The 4% rule is a rough guide, not a guarantee. Some retirees use a more conservative 3% to 3.5% for a longer horizon or more safety, while others adjust their spending flexibly year to year. Your right number depends on your time horizon, returns, and other income.
| Balance | 3% rule/yr | 4% rule/yr | 4% rule/month |
|---|---|---|---|
| $500,000 | $15,000 | $20,000 | ~$1,667 |
| $750,000 | $22,500 | $30,000 | ~$2,500 |
| $1,000,000 | $30,000 | $40,000 | ~$3,333 |
What is sequence-of-returns risk?
Two retirees with identical average returns can have very different outcomes depending on when the bad years hit. A market downturn in the first few years of retirement — while you are withdrawing — is far more damaging than the same downturn later, because you are selling assets at low prices and they never fully recover.
This is 'sequence-of-returns risk,' and it is why the early years of retirement matter disproportionately. Strategies to manage it include keeping a cash buffer, staying flexible on spending in down years, and not being overly aggressive with investments right at retirement. Our 401k FAQ hub covers sequence risk and safe withdrawal rates.
How can you make your 401k last longer?
Several levers extend how long your savings last, and most are within your control. Small changes compound over a multi-decade retirement.
- Lower your withdrawal rate, especially in the early years.
- Delay Social Security to increase your guaranteed lifetime income.
- Keep some part-time income in early retirement to reduce withdrawals.
- Stay flexible: trim spending in down markets to protect the balance.
- Account for required minimum distributions from age 73, which may force withdrawals.
How do taxes and other income affect how long it lasts?
A 401k withdrawal from a traditional account is taxable as ordinary income, so the amount you can actually spend is less than the amount you withdraw. Planning around your tax bracket, and coordinating with Social Security and any pension, changes how much you truly need from the 401k each year.
Because so many variables interact — returns, inflation, taxes, longevity — projections are estimates rather than certainties. A 401k drawdown calculator lets you test different withdrawal amounts and return assumptions to see roughly when the balance would run out under each scenario.
Frequently asked
It lasts until inflation-adjusted withdrawals outpace returns and drain the balance. Under the 4% rule, a starting withdrawal of 4% of the balance is likely to last about 30 years. Lower withdrawals or higher returns extend it.