Coast FIRE Calculator (UK)
A Coast FIRE calculator for UK savers. Enter your pension and ISA investments to find your Coast FIRE number and the age you can stop contributing.
Coast FIRE Calculator
Discover if your current savings are enough to grow to your retirement goal without additional contributions. Get instant, accurate calculations with no signup required.
UK accounts to include
Count money invested for retirement: your workplace pension, SIPP, and Stocks & Shares ISA. Exclude cash savings and your home. The withdrawal-rate logic mirrors the US 4% rule, though some UK planners use a slightly lower rate to reflect different market history.
A UK worked example
Say you want 40,000 pounds a year in retirement. At a 4% withdrawal rate that is a 1,000,000 pound target. If you are 35 and plan to retire at 60, with a 5% real return over 25 years (1.05^25 is about 3.39), your Coast FIRE number is roughly 295,000 pounds. Once your pensions and ISAs add up to that, you can stop contributing and let the pots grow to 1,000,000 pounds by 60. Count only money actually invested for retirement - your workplace pension, SIPP, and Stocks & Shares ISA - and leave out cash savings and the value of your home.
The 4% rule in a UK context
The 4% rule comes from US market history, and some UK planners argue for a slightly lower withdrawal rate - often 3.5% - because UK and globally diversified portfolios have had different return and inflation patterns than the US-centric data behind the original studies. A lower withdrawal rate means a larger FIRE number and a larger Coast FIRE number, so it is a more cautious assumption. The calculator lets you set your own rate, so you can model 4%, 3.5%, or whatever fits your risk tolerance.
The State Pension and when it starts
Like Social Security in the US, the UK State Pension reduces how much your own investments need to fund - but it does not begin until State Pension age, which is currently 66 and rising to 67 and then 68 for younger savers. If you plan to retire before then, your portfolio has to bridge those gap years entirely on its own, so many UK FIRE savers leave the State Pension out of their Coast FIRE maths as a safety margin, or include it only for the years after it starts.
Pensions vs ISAs: access and tax
UK retirement money usually sits in two kinds of wrapper, and the difference matters for early retirement. Pension and SIPP money grows free of UK tax and gets tax relief on the way in, but you cannot access it until age 55 (rising to 57 in 2028). ISA money has no such age lock - you can withdraw it tax-free at any time - which makes ISAs especially valuable for bridging the years between an early retirement and pension access. For a Coast FIRE calculation the totals are what matter, but for the withdrawal plan that follows, the mix of pension and ISA shapes when you can actually spend it.