The calculator uses the annuity depletion formula to find how many months a lump sum will last at a fixed monthly withdrawal and constant investment return. If the monthly return on your balance exceeds your withdrawal, the portfolio never depletes. Pair this with the 401k Calculator with Match to see how much you will have saved by retirement before running this calculation.
The table below shows how long different savings balances will last at various monthly withdrawal amounts, assuming a 5% average annual return. Use this as a quick reference before running the calculator with your specific numbers. If you are in the early accumulation phase, the Coast FIRE Calculator shows how much you need saved today so compound growth covers retirement without further contributions.
| Savings Balance | $2,000/mo | $3,000/mo | $4,000/mo | $5,000/mo |
|---|---|---|---|---|
| $250,000 | 15 years | 9 years | 6 years | 5 years |
| $500,000 | Forever | 24 years | 15 years | 11 years |
| $750,000 | Forever | Forever | 31 years | 20 years |
| $1,000,000 | Forever | Forever | Forever | 36 years |
Assumes 5% average annual return, no inflation adjustment. Enter your own numbers above for a precise result.
Inflation reduces how long savings last by lowering the real return on your portfolio. The calculator uses the real return formula to adjust for inflation: Real Return = (1 + Nominal Rate) / (1 + Inflation Rate) - 1. A 7% nominal return with 3% inflation gives a real return of about 3.9%, not 4%. The table below shows how the same portfolio scenario changes across inflation assumptions. Tax-advantaged accounts like a Roth IRA grow tax-free, which helps offset inflation over time. See the Roth IRA Contribution Calculator to check how much you can contribute annually.
| Inflation Rate | Real Return | Duration ($500k, $3,000/mo, 7% nominal) |
|---|---|---|
| 0% | 7.0% | 51 years |
| 1% | 5.9% | 29 years |
| 2% | 4.9% | 23 years |
| 3% | 3.9% | 20 years |
| 4% | 2.9% | 18 years |
Social Security income reduces how much you need to withdraw from personal savings each month, which significantly extends portfolio longevity. To use this calculator correctly, enter only the gap between your total monthly spending and your fixed income sources (Social Security, pension, rental income). Do not enter your total living expenses.
Delaying Social Security from age 62 to 70 increases your monthly benefit by approximately 77%. This reduces the required monthly withdrawal from savings, often extending portfolio life by 10 or more years. The tradeoff is drawing down savings faster in the early retirement years before Social Security kicks in.
You retire at 65 with $600,000 saved. You plan to withdraw $3,500 per month. You expect a 6% nominal portfolio return and 2.5% inflation. Check how much you should have saved before retiring with the Coast FIRE Calculator.