What FIRE means and how this calculator works

FIRE stands for Financial Independence, Retire Early. The core idea is accumulating enough investment assets that passive growth can cover living expenses indefinitely. This calculator simulates monthly compounding on your current savings plus ongoing contributions until your portfolio reaches a target amount you define. If the target is not reached within 70 years, the calculator shows your balance at that point.

Important caveats

A fixed annual return assumption is a simplification. Sequence-of-returns risk, inflation, taxes, and healthcare costs are not modeled here. The target amount you choose (often based on the 4% withdrawal rule) involves its own assumptions about spending and longevity. Treat these projections as one data point in a broader planning process.

Method and limits

Formula

balanceₘ = balanceₘ₋₁ × (1 + r_month) + contribution ; 목표 도달 시점 = min{ m : balanceₘ ≥ target }

Worked example

With zero starting assets, 2,000 USD saved monthly and an assumed 7% return, a 1,000,000 USD target is reached in about 19 years 11 months. The tool finds the first month where balanceₘ ≥ target, so raising the monthly amount visibly shortens that horizon.

Assumptions

Returns, yields, and inflation are assumed constant for the whole period at the value you enter. Real markets are not.

All math runs in your browser; inputs are never sent to a server.

Currency display uses a fixed exchange rate captured on the date below, not a live rate.

What is not included

Taxes (dividend/capital gains), trading commissions, currency conversion costs

How to verify this yourself

Put the same inputs into the formula above in a spreadsheet — you should reproduce these results exactly.

If you find an error, tell us via the contact page and we will verify and correct it. Contact