FIRE Calculator

Understand your path to financial independence. Make your own decisions. Take control of your future.

Calculate your Coast, Lean, and Fat FIRE numbers — and see exactly how far you are from financial independence.

Current Investable Savings

Monthly Savings Contribution

Annual Savings Increase

Step up your monthly contribution this % each year (e.g. with raises)

Expected Annual Return (real)

Use 7% for nominal, 4–5% for inflation-adjusted

Target Annual Spending in Retirement

Base case spending (Fat FIRE = 1.25×, Lean = 0.8×)

Current Annual Spending

Used for savings rate calculation

Safe Withdrawal Rate

4% is the classic rule; 3.5% is more conservative

Lean FIRE

$1,600,000

Minimum viable retirement spending

13% there

14.4 years

at current savings rate

Fat FIRE

$2,500,000

Comfortable retirement lifestyle

8% there

18.9 years

at current savings rate

Coast FIRE

$328,418

Amount that grows to Fat FIRE without more contributions

61% there

—

at current savings rate

What is Coast FIRE?

At Coast FIRE ($328,418 in today's dollars), your current savings — left alone — will grow to your Fat FIRE target by traditional retirement age. You could stop adding to investments and still retire comfortably. You just need to cover your living expenses from earned income.

You are 61% of the way to Coast FIRE ($128,418 more needed)

Ask AI Tutor about my FIRE plan →

Educational disclaimer: All content on WealthSerene.com is for educational purposes only and does not constitute investment advice. Projections and calculations are illustrative — actual results will vary based on market conditions, your specific situation, and many factors outside this tool’s scope. Always consult a qualified financial professional for advice specific to your situation. View full disclosures →

Save results

How this is calculated

We find your financial-independence number from your spending and a safe withdrawal rate, then project how long until your savings reach Lean, Coast, and Fat FIRE.

The steps

FIRE number = annual spending ÷ safe withdrawal rate (4% → 25× spending). Lean ≈ 0.8× and Fat ≈ 1.25× that target.
Grow current savings + monthly contributions month by month at your expected return.
Record the year your balance first crosses each FIRE threshold.
Coast FIRE = the amount needed today that would grow to your Fat target by age ~65 with no further contributions.