FIRE (Financial Independence, Retire Early)
A movement focused on aggressive saving and investing to achieve financial independence — the point where investment income covers living expenses — and optional early retirement.
FIRE adherents typically aim to save 50-70% of their income and invest it in low-cost index funds. The target is a portfolio large enough that a sustainable withdrawal rate (usually 4%) covers annual expenses indefinitely. The 'FIRE number' is annual expenses divided by the withdrawal rate — so £25,000/year expenses at 4% requires a £625,000 portfolio.
Variants include Coast FIRE (stop contributing and let compounding reach your target by a later date), Lean FIRE (minimal expenses), and Fat FIRE (comfortable lifestyle). UK FIRE planning must account for pension access ages (55/57), ISA limits, and the different tax treatment of pensions vs ISAs.
This calculator provides estimates based on 2025/26 tax rates and is not financial advice. Scottish taxpayers are subject to different income tax rates and bands. The calculations assume your salary is your only source of income and do not account for benefits in kind or other taxable income.
For personalised guidance on your pension contributions, speak to an FCA-regulated financial adviser. You can find one via Unbiased or VouchedFor.