Coast FIRE in the UK: your number in pounds

Coast FIRE, in pounds

You've hit Coast FIRE when your investments, left alone with no further contributions, will compound to your full retirement number by the age you plan to retire. You still work to pay today's bills, but retirement saving is finished.

Two numbers drive it. Your FIRE number is annual spending ÷ withdrawal rate: £25,000 a year at 4% means £625,000. Your Coast FIRE number discounts that back to today at your real return, meaning growth after inflation:

Coast FIRE number = FIRE number ÷ (1 + real return)^{years to retirement}

For a £625,000 target at 60, assuming a 5% real return, the threshold at each age is:

A 30-year-old needs less than a quarter of the final number. That's the whole appeal: the earlier you front-load, the sooner saving becomes optional. See Coast FIRE targets by age for more combinations.

The UK account stack

Where the money sits matters as much as how much there is, because UK accounts unlock at different ages:

• Workplace pension with employer match. Fill the match first, it's the closest thing to free money in the whole plan. Contributions get tax relief and compound untouched.
• Stocks & Shares ISA, £20,000 annual allowance. Growth and withdrawals are tax-free, and crucially the money is accessible at any age. This is your flexibility layer.
• SIPP. Same tax treatment as a workplace pension with full investment control, useful for the self-employed or for topping up beyond the workplace scheme.

The catch: pension money, workplace or SIPP, is locked until the normal minimum pension age, which rises from 55 to 57 in 2028. The State Pension arrives later still, at 67, rising to 68 for younger workers. So a UK early-retirement plan naturally splits into phases: ISA money bridges any years before 57, pensions carry you from 57, and the State Pension tops you up from 67 or 68. Your Coast FIRE pot needs the right split, not just the right total.

How the State Pension shrinks your number

US FIRE maths usually assumes your portfolio does everything forever. UK maths gets a large late-life subsidy. The full new State Pension currently pays roughly £12,000 a year, call it that for round numbers. On a £25,000 budget, once it starts your portfolio only needs to produce about £13,000 a year, and £13,000 × 25 is £325,000, roughly half the headline £625,000.

You still need the larger figure to cover the years between retiring and State Pension age, but modelling the two phases honestly, full drawdown to 67 or 68, half drawdown after, means many UK savers need meaningfully less than the simple 25× figure suggests. A qualifying National Insurance record is what earns the full amount, so check your State Pension forecast on GOV.UK before you lean on it. If you're decades away, it's sensible to treat the State Pension as a cushion rather than a certainty, run your numbers both with and without it and aim somewhere between the two.

A worked example: 30 years old, retiring at 60

Priya is 30, spends £25,000 a year, and wants the option to retire at 60. Her FIRE number is £625,000, and her Coast FIRE number today is about £145,000. She has £35,000 invested, £25,000 in her workplace pension and £10,000 in an ISA, and between her own contributions and her employer's match, £1,000 a month goes into the markets.

At a 5% real return, her pot grows while the coast threshold for her age also creeps up. The two lines cross at around age 43, when her portfolio reaches roughly £280,000, the coast number for a 43-year-old retiring at 60. From that point she could stop contributing entirely and growth alone should carry her to about £625,000 by 60, with pension access already open at 57 and the State Pension arriving at 68 to halve what her pot must produce. In practice she'll probably keep taking the employer match, which simply pulls the whole timeline forward. Run your own version with the Coast FIRE calculator and check your savings rate against the timeline you want.

How UK Coast FIRE differs from the US version

Most Coast FIRE content is written for Americans, and two of their biggest problems simply don't apply here. There's no Medicare cliff to bridge, the NHS covers you at every age, so you don't need to price decades of private health premiums into your spending figure. And the State Pension subsidy above has no clean US equivalent in most FIRE plans.

The UK's twist runs the other way: access ages. An American can, with some manoeuvring, tap retirement accounts early; a UK pension is genuinely sealed until 57. That makes the ISA-versus-pension split the most important design decision in a UK plan, where an American would be debating withdrawal strategies instead. If full coasting still looks distant, Barista FIRE, part-time income covering part of your spending, works identically in pounds, and the comparison of every FIRE type shows where each fits. Your full target is always worth a sense-check with the FIRE number calculator.

Frequently asked questions