FIRE Calculator — Find Your Financial Independence Number
Enter your income, expenses, and current savings. See your FIRE number and exactly how many years until you can retire early.
How the FIRE Calculator Works
The calculator uses two core principles: the 4% rule to determine your FIRE number, and 7% annual portfolio growth to project how long it takes to get there.
Step 1 — FIRE Number: Multiply your annual expenses by 25. This is how much you need invested so that a 4% annual withdrawal covers your costs indefinitely. Example: $60,000/year in expenses × 25 = $1,500,000 FIRE number.
Step 2 — Years to FIRE: Starting from your current savings, the calculator adds your annual savings each year and grows the balance at 7% (historical average for a diversified stock index). It counts the years until the balance reaches your FIRE number.
Step 3 — Savings rate: (Income − Expenses) ÷ Income. This is the most important lever — small changes in savings rate create enormous changes in your FIRE timeline.
The Most Important Insight: Savings Rate Beats Income
Two people earning $100k: one saves 20% ($20k/year), one saves 50% ($50k/year). The first has a FIRE timeline of ~37 years. The second: ~17 years — 20 fewer years of working. The difference isn't income, it's the rate of saving.
Higher savings rate works doubly: you invest more every year AND your lifestyle costs less, so your FIRE number is smaller. A person spending $40k/year needs $1M to retire. A person spending $80k/year needs $2M. Same income, 2× the target.
Frequently Asked Questions
How does the FIRE calculator work?+
The FIRE calculator uses the 4% rule: your FIRE number = annual expenses × 25. Then it calculates how many years until your investments reach that target, assuming 7% annual growth (the historical average for a diversified index fund portfolio, before inflation). It accounts for your existing savings as the starting balance.
What is FIRE?+
FIRE stands for Financial Independence, Retire Early. It's a lifestyle movement focused on extreme saving and investing — typically 50–70% of income — to build a portfolio large enough to fund living expenses indefinitely. The movement has several variants: Lean FIRE (very frugal), Fat FIRE (maintain high spending), Barista FIRE (part-time work), and Coast FIRE (stop contributing, let investments compound).
What is the 4% rule?+
The 4% rule comes from the Trinity Study (1998), which found that a portfolio of 50–75% stocks historically survived 30 years of 4% annual withdrawals in all historical periods. For early retirees with 40–50 year retirements, many experts recommend 3–3.5% to be safe. The 25× rule (your FIRE number) is derived from the 4% rule: 1 ÷ 0.04 = 25.
How much should I save to retire early?+
Your savings rate determines your FIRE timeline more than anything else. At a 10% savings rate, you need ~46 years. At 30%: ~28 years. At 50%: ~17 years. At 70%: ~8 years. The math works because a higher savings rate simultaneously increases what you save AND decreases what you need to retire on (lower lifestyle cost = lower FIRE number).
Does the FIRE calculator assume Social Security?+
No — this calculator is conservative and does not include Social Security income. If you plan to receive Social Security benefits, your actual FIRE number may be lower. Many FIRE practitioners exclude it for safety, treating SS as a bonus. You can manually reduce your annual expenses by your expected SS benefit to model this.