Question 1

What is a FIRE number?

Accepted Answer

Your FIRE (Financial Independence, Retire Early) number is the investment corpus needed to sustainably fund your living expenses indefinitely, calculated as your annual expenses divided by your chosen safe withdrawal rate.

Question 2

What is the difference between Lean, Regular, and Fat FIRE?

Accepted Answer

Lean FIRE targets a stripped-down budget (roughly 70% of typical expenses) for a minimal but sustainable lifestyle. Regular FIRE covers your actual current spending level. Fat FIRE targets a more comfortable lifestyle (roughly 150% of current expenses), giving more cushion for travel, healthcare, or lifestyle upgrades in retirement.

Question 3

Why does the withdrawal rate matter so much?

Accepted Answer

A lower withdrawal rate (say 3% instead of 4%) means a larger corpus is needed for the same annual spending, but gives a bigger safety margin against market downturns and a longer time horizon — important if you plan to be retired for 40+ years rather than the traditional ~25-30.

Question 4

Does this account for inflation after I retire?

Accepted Answer

Not directly — this shows your FIRE number in today's rupees based on today's expenses. The safe withdrawal rate itself (like the 4% rule) is designed to be inflation-adjusted year over year once you start withdrawing, but your expenses between now and retirement will still grow with inflation, which this simple calculator doesn't project forward.

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