FIRE Calculator

What is a FIRE Calculator?

A FIRE calculator helps you determine how much money you need to save to achieve Financial Independence, Retire Early. By entering your current expenses, savings rate, expected investment returns, and target retirement age, the calculator projects when your portfolio will reach your "FIRE number" — the amount needed to sustain your lifestyle indefinitely through investment returns alone.

Unlike traditional retirement calculators that target age 65, a FIRE calculator is designed for people who want to retire years or even decades earlier. It accounts for inflation, real investment returns, and the relationship between your withdrawal rate and portfolio longevity, giving you a clear roadmap to financial freedom.

How to Use This Calculator

1. Enter your annual expenses. Use your current yearly spending as a baseline. This is the most important input — your FIRE number is a direct multiple of it.
2. Set your ages and portfolio. Input your current age, target retirement age, and existing portfolio value to establish the starting point for projections.
3. Adjust your savings and returns. Enter how much you save per year and your expected annual investment return. A 7% nominal return is a common long-term assumption for a diversified stock portfolio.
4. Review your FIRE number and timeline. The calculator shows both your nominal FIRE number and the inflation-adjusted target, plus exactly how many years until your portfolio reaches that goal.

Frequently Asked Questions

What is the 4% rule?

The 4% rule states that you can withdraw 4% of your portfolio in the first year of retirement, adjust that amount for inflation each subsequent year, and have a high probability of your portfolio lasting 30 years. It originated from the 1994 Trinity Study, which analyzed historical stock and bond returns. For early retirees with longer time horizons, many FIRE practitioners use a more conservative 3–3.5% withdrawal rate instead.

What is a good FIRE number?

Your FIRE number is calculated by dividing your annual expenses by your planned withdrawal rate. With the standard 4% rule, your FIRE number is 25× your yearly spending. For example, if you spend $50,000 per year, your FIRE number is $1,250,000. Adjusting for inflation between now and your target retirement date gives you the actual nominal portfolio size you need to accumulate.

How does inflation affect my FIRE date?

Inflation erodes your purchasing power over time, meaning your future FIRE number must be larger in nominal terms than in today's dollars. If inflation averages 3% and you plan to retire in 20 years, a real $1,250,000 goal actually requires accumulating about $2,254,000 in nominal dollars. This calculator uses live CPI data when available so your projections reflect realistic economic conditions.

What return rate should I use?

A 7% nominal annual return is a widely used assumption based on long-term US stock market averages. After subtracting a 3% inflation assumption, this implies a 4% real return — which aligns directly with the 4% withdrawal rule. For a conservative estimate you might use 5–6% nominal; for a more aggressive scenario, 8–9%. The right rate depends on your asset allocation and risk tolerance.

What is Coast FIRE?

Coast FIRE is a milestone where your current portfolio, left to grow without additional contributions, will reach your full FIRE number by your target retirement age through compounding alone. Once you've "coasted," you only need to earn enough to cover current living expenses — you can stop saving aggressively. It's most powerful when reached early in life, allowing decades of uninterrupted compounding to do the heavy lifting.