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FIRE Calculator

Your Coast, Lean and Fat FIRE numbers, and how far you are from each at your current savings rate.

About 5 minutesFree, no account

Your numbers

$
$
Step up your monthly contribution by this much each year, for example with raises.
%
Use 7% for nominal, 4 to 5% for inflation-adjusted.
%
Base case. Fat FIRE is 1.25 times this, Lean FIRE 0.8 times.
$
Used for the savings rate.
$
4% is the classic rule; 3.5% is more conservative.
%

Lean FIRE

$1,600,000

Minimum viable retirement spending.

Progress
13% there

14.4 years at the current savings rate

Fat FIRE

$2,500,000

A comfortable retirement lifestyle.

Progress
8% there

18.9 years at the current savings rate

Coast FIRE

$328,418

The amount that grows to Fat FIRE with no more contributions.

Progress
61% there

— at the current savings rate

What is Coast FIRE?At Coast FIRE ($328,418 in today's dollars), your current savings, left alone, grow to your Fat FIRE target by traditional retirement age. You could stop adding to investments and still retire comfortably; you only need to cover living expenses from earned income.
You are 61% of the way to Coast FIRE, with $128,418 more needed.
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

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

Assumptions

  • Default 4% withdrawal rate and 7% return.
  • Spending in today’s dollars; returns are an average.

Good to know

  • The 4% rule is a historical guideline, not a guarantee — long retirements may warrant 3–3.5%.
  • Ignores taxes and sequence-of-returns risk.
Educational disclaimer. Everything on WealthSerene.com is educational and is not investment advice. Projections and calculations are illustrative; actual results depend on market conditions, your situation and factors outside this tool’s scope. For a decision specific to your situation, consult a qualified financial professional. View full disclosures