FIRE Calculator: Your Financial Independence Number

How the number is worked out

A common starting point is 25 times your annual spending, based on withdrawing about 4 percent a year. Lower spending lowers the target directly.

Savings rate does the heavy lifting

The share of income you keep matters far more than the exact return you assume. Raising it shortens the timeline in a way small return changes never do.

How it works

You enter your yearly spending, what you already have invested, how much you save each year, your income, an expected return, and a safe withdrawal rate. The calculator turns your spending into a FIRE number, grows your investments year by year with your savings added, and shows when the balance could reach that number. It also shows Lean and Fat FIRE targets and your savings rate so you can see which lever matters for you.

The formula in plain language

Your FIRE number equals your yearly spending divided by your safe withdrawal rate, so at a 4 percent rate it equals your yearly spending multiplied by 25.

A worked example

If you spend $48,000 a year and use a 4 percent withdrawal rate, your FIRE number is $1,200,000. If you earn $75,000 and save $12,000 of it each year, your savings rate is 16 percent.

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Frequently Asked Questions

What is my FIRE number?

Your FIRE number is the invested amount that can cover your annual spending indefinitely. With the 4% rule it's annual expenses × 25. Spending $50,000 a year means a FIRE number around $1.25 million. Using a more conservative 3.5% withdrawal rate raises it to about $1.43 million.

What is the 4% rule and is it still valid?

The 4% rule comes from research on historical U.S. market returns suggesting a portfolio could support withdrawals of 4% of its starting value, adjusted for inflation, over a 30-year retirement. It's a planning heuristic, not a guarantee, longer retirements, higher fees, or a bad first decade of returns can break it, which is why many people plan at 3.25%-3.75% instead.

What's the difference between Lean FIRE, regular FIRE, and Fat FIRE?

Lean FIRE covers a deliberately minimal budget (often under $40,000 a year). Regular FIRE covers your current lifestyle. Fat FIRE targets a comfortable budget with travel and margin. Coast FIRE is different again: you invest enough early that existing investments grow into your FIRE number by traditional retirement age without new contributions.

How do I calculate Coast FIRE?

Coast FIRE is the amount you need invested today so that, with no new contributions, it grows into your full FIRE number by the age you want to stop working. Take your FIRE number and divide it by (1 + expected real return) raised to the number of years left. Example: a $1.25 million FIRE number, 30 years away, at a 5% real return, means about $289,000 invested now. Once you hit that, you can coast: cover your living costs and let compounding finish the job.

Does my savings rate matter more than my income?

Yes, your savings rate sets the timeline. Someone saving 50% of income needs roughly 17 years of expenses covered per year saved, so the math works far faster than for someone saving 10%, regardless of the salary. Cutting a recurring expense both lowers the FIRE number and raises the savings rate.

Should I count my home equity or Social Security?

Home equity generally doesn't count toward the FIRE number unless you plan to sell or rent it, because it doesn't produce income while you live there. Social Security can reduce the portfolio you need in later years, but most FIRE plans exclude it as a conservative buffer, especially for early retirement before benefits begin.