Free · Fat FIRE
Fat FIRE Calculator
Stress-test Coast math with a richer lifestyle budget — travel, housing, and buffer included in today’s dollars.
Fat FIRE calculator
Free — Coast math with a higher spending lifestyle.
Today's dollars
401(k), IRA, brokerage — exclude home equity
Affects years to coast and projected value, not the Coast number; set 0 to test if you've already hit Coast
Assumptions
Fat Coast number
$711,056
USD
You need $641,056 more to coast (10% funded).
Fat FIRE number
$2,500,000
Years to coast
29 yrs
You have
$70,000
Real return
3.88%
Projected value
$3M
Monthly spending
$10,055
Today's value
$3,741
How is Fat FIRE calculated?
Fat FIRE uses the same formulas as classic FIRE — with a higher annual spend.
Fat FIRE nest egg ≈ high annual spend ÷ SWR · Coast = nest egg ÷ (1 + real return)^years
- Set a comfortable retirement spend (this page seeds a higher default).
- Pick SWR and return/inflation assumptions.
- Read Fat FIRE nest egg and today’s Coast checkpoint.
Start from the classic Coast tool if you want leaner defaults: Coast FIRE calculator.
Related calculators
Dial lifestyle up or down.
Fat FIRE notes
Lifestyle creep cuts both ways
A higher spend target raises the Coast line quickly. Revisit the number yearly — and keep invested assets labeled in Progress so Actual vs Goal stays honest.
Fat FIRE calculator FAQ
What is a fat FIRE calculator?
- A FIRE calculator seeded for higher annual spending so you can see the nest egg and Coast number needed for a more comfortable retirement lifestyle.
Is Fat FIRE the same as Coast FIRE?
- No. Fat FIRE is about a larger nest egg from higher spend. Coast FIRE is the today checkpoint so compounding can finish that nest egg.