FIRE calculator for the United Kingdom
UK early retirement usually runs on two pots: an ISA that can be drawn at any age, and a pension that cannot. Getting the split right is most of the planning work.
Open an investment account
We explain exactly what to compare before you open anything - costs, protection and the traps.
The bridge and the main pot
The stocks and shares ISA funds the years between stopping work and the age your pension unlocks. The SIPP or workplace pension is the larger, tax-relieved pot behind it.
Higher and additional rate taxpayers get substantial relief on pension contributions, which is why many UK plans overweight the pension and size the ISA to exactly cover the bridge years.
Set the withdrawal rate deliberately
UK historical returns and inflation differ from the US data behind the 4% rule, and a retirement starting in your early fifties may need to last forty years. A rate of 3.5% is a common UK planning choice.
Change it above and the FI number responds immediately, which is the fastest way to see how much certainty costs.
Frequently asked questions
What is my FIRE number in pounds?
Annual spending divided by your withdrawal rate. At 3.5%, spending of 32,000 a year points to roughly 914,000.
ISA or pension first?
Pensions win on tax relief, ISAs win on access. Most plans use both: enough ISA to bridge to pension age, the rest in the pension.
When can I access my UK pension?
Access ages have been subject to change. Check the current minimum pension age for your own birth year before building a bridge around it.
Does the State Pension change the number?
Yes, from the age it starts. It reduces what your own portfolio must cover for the rest of your life, though not during the early years.
Get the FIRE Action Plan
Your FI number, target date and the monthly investment that hits it, with Coast, Lean and Fat milestones.
No spam, and one click unsubscribes. We never sell your details. See our privacy policy.
Keep going
Want the FIRE Action Plan?
Your FI number, target date and the monthly investment that hits it, with Coast, Lean and Fat milestones.
One email, then a short weekly note. Unsubscribe any time.