🔥 FIRE Calculator for Couples

Your FIRE number is calculated as 25 times your annual expenses as a couple. This is based on the "4% rule" — a widely used guideline suggesting you can withdraw 4% of your portfolio each year in retirement without running out of money.

FIRE Number = Monthly Expenses × 12 × 25

Example: If you need $5,000/month as a couple → $5,000 × 12 = $60,000/year → $60,000 × 25 = $1,500,000

The default 7% return is a real return — it already accounts for inflation. Historically, a diversified stock portfolio has returned roughly 10% per year, minus about 3% inflation, giving ~7% real growth. Because the return is inflation-adjusted, your FIRE number stays in today's dollars — the number you can actually relate to your current life.

If you want to be more conservative, simply lower the return rate (e.g., 5% or 6%) to stress-test your plan. This is more intuitive than adding a separate inflation variable.

Your FIRE number is based on your shared expenses as a couple — not the sum of two individual FIRE numbers. This is one of the biggest advantages of pursuing FIRE together: shared housing, utilities, insurance, and daily costs mean your target is significantly lower than if you were each planning alone.

Monthly contributions are kept separate because each partner may invest different amounts, and one may stop contributing before the other. But the goal — your FIRE number — is shared.

When you enter finances per partner, each partner's investment pool grows independently at its own rate. This matters because different investment strategies (aggressive vs. conservative, stocks vs. bonds) produce different returns, and each partner's monthly contributions feed their own pool.

When entering as a couple, all investments are treated as a single pool with one growth rate — simpler and perfectly fine if you invest similarly.

In both modes, the FIRE check is the same: your combined net worth (all cash + all investments − debt) needs to reach your FIRE number.

This is what makes a couples calculator different from running two individual calculations. If one or both partners plan to stop investing before FIRE — to raise children, change careers, semi-retire, or pursue other goals — the calculator shows you the impact:

• One partner stops: The other partner's contributions continue, and the stopped partner's portfolio keeps growing from returns alone
• Both partners stop (at different times): After the last partner stops, your entire portfolio grows only from compound returns — no new contributions
• Both stop at the same time: Equivalent to both stepping back simultaneously; growth continues from returns only
• Result: The calculator shows exactly how many additional years each scenario adds to your FIRE timeline

This lets you plan realistically and decide together what timeline works for your life.

Your investments grow monthly based on the average return you specified. This compounds over time — meaning you earn returns on your returns. We use the proper compound interest formula to convert annual returns to monthly rates.

Monthly Return = (1 + Annual Return)^1/12 − 1

Example: 7% annual return → (1.07)^1/12 − 1 = 0.565% per month. On $100,000 → grows by ~$565 that month, plus your monthly contribution

Using the 4% rule, withdrawing 4% of your FIRE number annually gives you your target annual spending as a couple:

4% of FIRE Number = Annual Expenses

Example: 4% of $1,500,000 = $60,000/year = $5,000/month for both of you

Note: This calculator provides estimates based on historical averages and the 4% rule as a starting guideline. Real-world results vary based on market performance, actual inflation rates, tax situations, and life changes. The 4% rule is a planning tool, not a guarantee — consider consulting with a financial advisor for personalized planning.