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Investing · Trinity Study

FIRE Calculator

Financial Independence, Retire Early — the FIRE movement targets a pot 25× annual spend, then withdraws 4% per year. This shows when you’d get there at your current savings rate.

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£
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Years to FI

21.9

Numbers

  • Target pot (× 25.0)
    £750,000
  • Monthly draw at SWR
    £2,500

How we calculated your result

Target pot = annual spend ÷ SWR. We then solve the future-value equation analytically: how many years until current invested + monthly savings × growth = target. Returns are in real (after-inflation) terms.

Official UK rules in simple English

  • Trinity Study (1998, US): 4% withdrawal had a 95%+ 30-year success rate.
  • UK studies (Pfau, Cooley) suggest 3.0–3.5% is safer due to lower equity returns.
  • SIPP + ISA combo gives the most tax-efficient path in the UK.

Common pitfalls to watch out for

  • ⚠ 4% is US-data; UK is lower

    UK equity returns have historically been ~1pp lower than US. Use 3.5% for a margin of safety.

  • ⚠ Sequence-of-returns risk

    A bear market in years 1–5 of retirement is devastating. Hold 2 years of cash as a buffer.

  • ⚠ State Pension lifts SWR

    Once SP kicks in (age 67/68), your pot only has to cover the gap. Often the harder bridge is age 50–67.

Frequently asked questions

Why 25×?
1/0.04 = 25. The 25× rule is just the 4% SWR restated as a multiplier.
Is FIRE realistic on UK salaries?
Aggressive savers (50%+ of income) can hit it in 15–20 years. Standard 15% pensioners get there at the State Pension age.

Educational. Investment returns aren’t guaranteed — speak to a financial planner.

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