Calculation method
Divide inflation-adjusted retirement spending by the chosen withdrawal percentage, then discount the nominal retirement target to today using the effective annual nominal return. No future contributions are assumed.
Retirement · General formulas
Coast FIRE Calculator
Estimate investments needed today to reach a retirement target without further contributions using your own return, inflation and withdrawal assumptions. Use the example values or enter your own numbers to explore an estimate.
Currency formatting only—not an exchange-rate conversion. No country-specific tax or government rules are applied.
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The PDF includes active input values and option labels, results, sources, model assumptions, and the schedule when available. Schedule periods follow the model: years, months, or actual payments.
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Links include eligible rate, term or frequency assumptions only. Dollar amounts are never included. Recipients must enter their own amounts; the link will not reproduce your full financial scenario.
Assumptions & limits
- Example: a 1,000,000 target in 10 years at 0% inflation and 0% return requires 1,000,000 today.
- The withdrawal assumption defines a target, not guaranteed safe income. No taxes, pensions, fees, sequence risk or post-retirement simulation.
- Basis: User-entered values.
- Basis: Standard fixed-payment and time-value-of-money formulas.
Source/rule review year: Not applicable — general mathematical model.
Compare like with like
A nominal annual rate is not the same as an effective annual return. With nominal rate r compounded m times per year, the equivalent effective annual rate is (1 + r / m)m − 1. For example, 6% nominal compounded monthly is about 6.17% effective for a year before fees, taxes, or inflation.
Contribution and withdrawal timing also matters: end-of-month deposits miss that month’s growth, while a beginning-of-period deposit earns for the full period. Compare tools only after matching the rate convention, compounding period, contribution timing, and fees; a displayed equivalent does not make distinct models identical.
Read the compound-interest guide