FIRE Number
Estimate the nest egg you'd need to retire using the 4% rule — 25 times your annual spending. See both the total target and the monthly income it's meant to cover.
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💡 Good to know: The "4% rule" comes from the 1998 Trinity Study, which found that withdrawal rate rarely drained a portfolio over 30 years.
Worked example
FIRE number: $1,000,000.00 · Monthly need: $3,333.33
How it’s solved
Worked on the example above, step by step — follow along and you can do it on paper next time, no tool required.
- The 4% rule says you can retire on about 25× your annual spending.
- FIRE number = annual spend × 25
$40,000.00 × 25 = $1,000,000.00 - Monthly income it must cover = annual ÷ 12
$40,000.00 ÷ 12 = $3,333.33
Learn the method
Inputs
- Annual spend $
40000
Frequently asked
What is the 4% rule?
The idea that you can withdraw 4% of a portfolio each year with low risk of running out, so 25× annual spending is your target.
Is the 4% rule guaranteed?
No — it's a historical rule of thumb. Market conditions, longevity and spending changes can move the real number, so treat it as a planning baseline.