By the UK Tax Drag editorial team · Reviewed 2 May 2026

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

Current age

1870

Target FIRE age

3075

Current investments (£)

£0£2m

Monthly savings now (£)

£0£10k

Annual spend (retirement) (£)

£10k£200k

Real return pre-FIRE (%)

0%10%

Real return post-FIRE (%)

0%8%

Safe withdrawal rate (%)

2.5%5%

State Pension (age 67+) (£/yr)

£0£15k

State Pension age

5575

Inflation assumption (% — for reference)

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

Target gapWaiting for a FIRE gap estimate.

Bridge to State PensionWaiting for bridge-fund detail.

Best next leverSavings rate, target spending and wrapper mix matter more than tiny return tweaks.

What this means

The professional use of a FIRE estimate is to separate three jobs: the bridge before State Pension age, the long-run withdrawal rate after that, and the wrapper mix that funds both without unnecessary tax drag.

Professional read

How to read the FIRE result properly

A serious FIRE plan is not one pot and one withdrawal rate. It is a sequence problem, a wrapper problem, and a spending-discipline problem all at once.

Key assumptionsThis model assumes smooth long-run returns, the contribution pattern you entered, and a steady spending target rather than real-world lumpy withdrawals.

Common mistakeUsing a FIRE number as if it automatically solves the bridge before State Pension age or the wrapper mix needed to fund that bridge tax-efficiently.

Best next actionStress-test the spending target, then compare the bridge years separately from the post-State-Pension years before treating the headline number as a decision point.

When this breaks downSequence risk, market valuation, one-off spending shocks, and pension access timing can all make a simple FIRE multiple look cleaner than reality.

Professional note. The most useful improvement after a FIRE result is usually not a higher assumed return. It is a better savings rate, a tighter spending plan, or a cleaner wrapper strategy.

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.

Age	Year start pot	Contribution	Growth	Withdrawal	Year 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 rate	Years to FIRE	Example: £30k spend
10%	51.3	Save £3.3k/yr
20%	37.4	Save £7.5k/yr
30%	27.6	Save £12.9k/yr
40%	22.1	Save £20k/yr
50%	17.2	Save £30k/yr
60%	12.5	Save £45k/yr
70%	8.5	Save £70k/yr

Types of FIRE

Lean FIRE: £15-20k annual spend. Minimalist lifestyle, maximum flexibility.
Regular FIRE: £25-40k annual spend. Comfortable but not extravagant.
Fat FIRE: £50k+ annual spend. More luxuries, same financial independence principle.
Coast FIRE: Stop contributing to investments now, let them grow until traditional retirement age (67+). You'll have enough then without adding another pound.
Barista FIRE: Reduce to part-time work (e.g., 1 day/week) to cover living costs, let investments grow untouched.

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 type	Use case	Withdraw from
Lifetime ISA	Bridge fund + retirement top-up (£4k/yr cap + 25% govt bonus)	Age 60+ or first home
Stocks & Shares ISA	Bridge fund (tax-free growth, no CGT on withdrawal)	Any age
General Investment Account	Overflow bridge, post-ISA allowance	Any 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 pension	Employee + employer contributions, often locked until 55+	Age 55+ (rising to 57)

years of retirement can

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

Calculator Methodology

How to use this FIRE output professionally

This is a planning model, not a promise. The professional read of a FIRE result is whether the target spending level is realistic, how the bridge before State Pension age is funded, and whether the wrappers you plan to use actually match the withdrawal timeline.

Last reviewed

22 April 2026
UK retirement-planning context for 2026/27

Who this is for

People mapping financial independence using ISA, GIA and pension wrappers rather than only checking a simple 25x rule

Main assumptions

Constant real returns, fixed real spending, and a simplified State Pension bridge
No explicit tax on withdrawals, asset allocation glide path, or sequence-specific stress test

Best companion pages

What To Open Next

Turn the FIRE estimate into a real wrapper and withdrawal plan

The headline FIRE number is only useful once you know which parts sit in pension wrappers, which parts need to stay accessible, and how much tax drag appears if the bridge is funded outside an ISA.

Pension calculatorModel the later-life pension sleeve separately from the pre-pension bridge. ISA vs GIACheck the tax drag if your bridge fund spills outside the ISA wrapper. Pensions guideUnderstand wrapper rules, access ages, and how the bridge interacts with pensions.

My scenarios

▸ How this calculator works — formulas, rates and assumptions

The core formula

FIRE number = annual expenses × 25 (the 4% safe withdrawal rule), adjusted for retirement length and asset mix.

What each input means

Annual spending	Current essentials + lifestyle in today's pounds.
Current savings/investments	Total liquid net worth available for retirement (excluding pension if not yet accessible).
Annual savings rate	How much you can save per year going forward.
Expected real return	After-inflation portfolio return — typically 4-5% for diversified equity.

2026/27 rates and thresholds used

Safe Withdrawal Rate (4% rule)	Trinity Study (Bengen 1994; Trinity 1998)
Recent SWR research suggests	3.5-4.5% depending on asset mix + retirement length
UK ISA allowance	£20,000/year (tax-free wrapper)
UK pension AA	£60,000/year (tax relief at marginal rate)

Key assumptions

Real returns averaging 4-5% over the long run (equity-heavy portfolio).
4% initial withdrawal rate, adjusted annually for inflation.
Retirement horizon of 30+ years (longer retirement → lower safe withdrawal).
No major asset re-allocation — stays at chosen equity/bond split throughout.

Known limitations / edge cases

The 4% rule was derived from US data 1926-1995 — UK history shows similar but not identical results.
Sequence-of-returns risk: a bad first decade can break the maths even if long-run returns are OK.
Doesn't model healthcare costs explicitly — UK NHS makes this easier than US but private care + care home costs can be significant.
Bridge-the-gap problem: most UK FIRE plans hit a "access pension at 57" hurdle before drawdown starts.

The calculator code is reviewed against current HMRC, FCA and MoneyHelper guidance on every page review (see the "Last reviewed" date above). Found an error? corrections@uktaxdrag.co.uk.

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