FIRE Calculator

When Can You Retire?

Financial Independence Retire Early. Find your FIRE number — the pot you need to cover your retirement spending — and see how many years it takes to get there. Includes UK State Pension and the 4% safe withdrawal rule.

Educational only. Returns assume constant annual real (inflation-adjusted) growth. Actual returns are volatile. State Pension projections are today's money. Not financial advice.

What is FIRE?

Financial Independence Retire Early (FIRE) is achieving a net worth large enough that your investment returns alone can cover your living costs forever. The traditional benchmark is 25 times your annual spending — which equates to the famous 4% safe withdrawal rate. In the UK, the State Pension cushions later years, so your investment pot only needs to bridge the gap until age 67 or later.

Your inputs

1870
3075
£0£2m
£0£10k
£10k£200k
0%10%
0%8%
2.5%5%
£0£15k
5575
0%6%
Your FIRE number
£0
investable pot needed
Current pot
£0
Projected at target age
£0
£0FIRE pot target
0Years to FIRE
0%Current savings rate
0xYears of spending covered
Pot trajectory to FIRE and beyond
Projected pot growth FIRE number target State Pension age

Year-by-year projection

This table shows your pot accumulation until FIRE age, then drawdown in retirement. Notice how State Pension arrival reduces the annual withdrawal needed.

AgeYear start potContributionGrowthWithdrawalYear end pot

Your savings rate is the biggest lever

The percentage of your income saved — not the absolute amount — determines time to FIRE. A 40% savings rate gets you there 4x faster than 10%. This classic table from the FIRE community shows years to FIRE at various savings rates (assuming 5% real return):

Savings rateYears to FIREExample: £30k spend
10%51.3Save £3.3k/yr
20%37.4Save £7.5k/yr
30%27.6Save £12.9k/yr
40%22.1Save £20k/yr
50%17.2Save £30k/yr
60%12.5Save £45k/yr
70%8.5Save £70k/yr

Types of FIRE

The Trinity Study and the 4% rule

The "4% rule" originated from the 1998 Trinity University study, which analysed 50 years of US stock/bond market data. It found a 4% withdrawal rate (25x annual spend) had a 95% success rate over 30 years. However, modern analysis suggests 3.25–3.5% is safer for UK-based investors planning 40+ year retirements. You can adjust the safe withdrawal rate above.

Tip: You can often increase SWR in practice

If you're flexible on spending — pulling back in bear markets, taking holidays only in good years — you might safely use 4% or even 4.25%. This calculator lets you explore different SWR assumptions to find your comfort zone.

UK-specific FIRE considerations

Bridge fund (pre-State Pension): Your pension pots (SIPP, workplace) are locked until 55/57, so you need a bridge in a General Investment Account or ISA to cover spending from FIRE age to State Pension age. This table shows a rough breakdown:

Investment typeUse caseWithdraw from
Lifetime ISABridge fund + retirement top-up (£4k/yr cap + 25% govt bonus)Age 60+ or first home
Stocks & Shares ISABridge fund (tax-free growth, no CGT on withdrawal)Any age
General Investment AccountOverflow bridge, post-ISA allowanceAny age (CGT applies, ~£3k exemption/year)
SIPP (personal pension)Main wealth-building wrapper (tax relief going in, 25% tax-free lump sum)Age 55+ (rising to 57)
Workplace pensionEmployee + employer contributions, often locked until 55+Age 55+ (rising to 57)
Sequence of returns risk

A major market crash in the first 2–3 years of retirement can devastate a FIRE plan, even if long-term returns are fine. Solution: keep a 3–5 year cash buffer before and during early FIRE years, or use a glide path (gradually move from stocks to bonds as you approach and enter retirement).

Compound interest calculator · Pension calculator · ISA vs GIA tax comparison · Salary sacrifice calculator

Official references & background reading
Bogleheads — Trinity Study (original 4% rule research) MoneyHelper — UK Pension freedoms and withdrawals FCA — Financial Conduct Authority guidance UK FIRE community forum GOV.UK — State Pension eligibility and rates
My scenarios