Question 1

What is a FIRE number?

Accepted Answer

Your FIRE number is the corpus, in today’s rupees, that can fund your chosen lifestyle from FIRE age through life expectancy. Earlier FIRE funds more years, so this number rises.

Question 2

Why does retiring earlier increase the FIRE number?

Accepted Answer

The headline figure is in today’s rupees. Cutting FIRE age lengthens the years you must fund, so the number goes up. The account balance on FIRE day can still look smaller because those rupees have had fewer years of inflation.

Question 3

How is this different from the 25× rule?

Accepted Answer

The 25× rule (4% withdrawal) is a US-market rule of thumb. Here the FIRE number is the present value of inflation-growing withdrawals over your years after FIRE, using your post-FIRE return. That is a growing annuity, not a multiple of one year’s spend.

Question 4

What is Lean, Classic and Fat FIRE?

Accepted Answer

They scale today’s annual expenses. Lean is 70%, Classic is 100%, Fat is 150%. Life expectancy then sets how many years that spend must be funded.

Question 5

How much SIP do I need for FIRE in India?

Accepted Answer

The SIP closes the gap between the corpus needed on FIRE day and the future value of what you already have, at your pre-FIRE return. Current corpus changes SIP, not the headline FIRE number.