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Lean FIRE vs Fat FIRE Calculator

Compare the portfolio and timeline needed for Lean FIRE, regular FIRE and Fat FIRE, based on your savings and spending levels.

Checked by the Money Years editors · Updated October 28, 2026 · How we calculate

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Three flavors of FIRE

FIRE comes in sizes. Lean FIRE means retiring on a tight budget, often under about $40,000 a year for a household, with little room for travel or surprises. Fat FIRE means a comfortable or even generous lifestyle, commonly $100,000 a year or more. Regular FIRE sits in between, and some people call the space between regular and fat "Chubby FIRE". There are no official cut-offs; the labels are relative to where you live and what you need.

Because the portfolio target is about 25 times spending, the gap between them is huge. Lean FIRE on $35,000 needs $875,000, while Fat FIRE on $120,000 needs $3 million. The calculator shows how many extra working years each step up costs at your current saving pace.

Picking your level

Lean FIRE gets you out sooner but leaves little margin, so a bad market or a health cost can force a return to work. Fat FIRE takes longer but builds in comfort and resilience. Many people aim for regular FIRE with a plan for flexible spending: cutting back toward lean in bad years and spending more in good ones.

Common questions

What is considered Lean FIRE?

Generally retiring on a minimal budget, often below roughly $40,000 a year for a household in the US.

What is Fat FIRE?

Retiring with a generous budget, commonly $100,000 or more a year, which needs a portfolio of $2.5 million or more.

Which is best?

It depends on your costs and comfort with risk. Many aim between the two with flexible spending.

This calculator gives estimates for planning. Real returns, rates and prices change, so treat the result as a guide rather than a promise. Read how we build and check our calculators.