How Long Will Retirement Savings Last Calculator
Stress-test a nest egg — enter balance, annual or monthly withdrawals, and expected real return to see years until depletion, or whether returns cover spending indefinitely. Click any i for detail.
Portfolio & spending
Current balance ($)
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Balance
Investable retirement portfolio (taxable + tax-advantaged combined if you want a single sketch). |
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Withdrawal amount ($)
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Withdrawal
Spending drawn from the portfolio each year or month (see basis). |
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Withdrawal basis
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Basis
Whether the withdrawal amount is annual or monthly. |
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Expected real return (%)
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Real return
Return after inflation. Example: 7% nominal − 3% inflation ≈ 4% real. |
How to use this calculator
- Enter today’s portfolio balance.
- Enter planned withdrawals (annual or monthly).
- Set an expected real (after-inflation) return.
- Read years until depleted — or Indefinite if returns cover spending.
Results explained
Headline shows duration. If monthly real growth on the starting balance covers the withdrawal, the model returns Indefinite rather than a finite year count.
Quick reference: depletion model
Simple constant-withdrawal sketch.
| Item | Detail |
|---|---|
| Order | Grow at real/12, then withdraw |
| Indefinite | Withdrawal ≤ starting balance × monthly real rate |
| Cap | Simulated up to 100 years |
Sequence-of-returns risk and changing spending are not modeled.
How the estimate is built
Each month: balance × (1 + real/12) − monthly withdrawal, until balance hits ~0. Closed-form sustainability check when withdrawal ≤ balance × monthly rate.
Example scenario
$850k, $40k/year, 4% real → withdrawal is below a pure 4% rule starting point, so duration is long; raise spending or cut return to see depletion sooner.
FAQ
Is this the 4% rule?
Related idea, but we simulate your numbers monthly instead of fixing a 30-year success rule.
Nominal vs real return?
Use real return and today’s-dollar withdrawals so inflation is netted out.
What does Indefinite mean?
Under constant return and withdrawal, the balance never runs out in this model.