What's the FIRE number for retire at 45 — what monthly savings does it take??

FIRE number = annual expenses × (100 / SWR). For $50,000/year expenses at 4% SWR: $50,000 × 25.0 = $1,250,000.

How many years to reach this FIRE number?

Starting with $50,000 and saving $4,000/month at 7% real return, you reach $1,250,000 in 15 years — at age 45. Total contributed: $770,000; growth: $480,000.

What savings rate does this require?

$48,000/year saved out of an implied $98,000 income = 49% savings rate. At this rate, FIRE in ~15 years aligns with Mr. Money Mustache's famous "shockingly simple math" — savings rate is the single biggest lever, more than income or rate of return.

What if my real return is different?

Bump to 8% real and FIRE comes ~2-3 years sooner. Drop to 5% and it takes 3-5 years longer. Real (after-inflation) returns matter more than nominal. The S&P 500 long-run real return is ~7%; use this for retirement planning unless you want to inflate your target.

FIRE scenario · Verified 2026-05-27

Retire at 45 — what monthly savings does it take?

FIRE number: $1,250,000 ($50,000/year × 25.0). At 7% real return saving $4,000/month from $50,000, you reach it in 15 years — age 45. Savings rate: 49%.

FIRE number

$1,250,000

Years to FIRE

FIRE age

Savings rate

49%

Run your own variations

The calculator below is pre-filled with this scenario's numbers — drag any input to see how it shifts your FIRE timeline.

How this number was calculated

FIRE number  = Annual expenses × (100 / SWR)
             = $50,000 × 25.0
             = $1,250,000

Years to FIRE: solve   bal × (1 + r) + annual_contrib = FIRE
  starting bal = $50,000
  annual_contrib = $48,000
  r (real return) = 0.07
  → 15 years

Total contributed  = $770,000
From growth        = $480,000  (38% of FIRE number)

Math grounded in the Trinity Study (Cooley et al., 1998) and Karsten Jeske's SWR Series.

Related FIRE scenarios

Retire at 50 starting at age 30

→ FIRE $1,250,000 in 19 years (age 49)

Retire at 55 with $60K/year expenses

→ FIRE $1,500,000 in 20 years (age 55)

Retire at 40 — only 10 years away from age 30

→ FIRE $1,000,000 in 10 years (age 40)

Retire at 35 starting in your mid-twenties

→ FIRE $1,000,000 in 11 years (age 36)

Run any FIRE scenario

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Educational projection. Future returns are not guaranteed. Sequence-of-returns risk matters for early retirees — see Karsten Jeske's SWR Series for nuanced analysis. Verified 2026-05-27.