---
title: "FIRE Calculator UK: FIRE Number, ISA, Pension & Early Retirement"
description: "Free FIRE calculator for the UK: your FIRE number, the monthly investment to retire early, your earliest FI age and Coast FIRE, with ISAs, pensions from 57 and the State Pension."
canonical: https://mywealthcheck.com/calculators/fire-calculator-uk/
language: en
updated: 2026-11-11
publisher: MyWealthCheck (hello@mywealthcheck.com)
note: Text copy of the canonical page, generated from the same build. For education only, not investment advice.
---
# FIRE calculator for the UK

To retire early in the UK you usually need 25 to 33 times your yearly spending at the age you stop working, with enough in ISAs and other savings to bridge the years until you can take your pension at 57. Enter five numbers to see your own FIRE number, the monthly investment that gets you there and your earliest FI age. Everything is in pounds and runs in your browser.

Free · any currency · no sign-up · method last reviewed 11 November 2026

> **Interactive tool.** This part of the page runs in the browser and is not included in this text copy. Open https://mywealthcheck.com/calculators/fire-calculator-uk/ to enter your own numbers.

## Quick answer: what is your FIRE number in the UK?

Your FIRE number is the amount invested that can pay your inflation-adjusted living costs from the age you stop working until your plan age (90 or later for early retirement). In the UK it is usually **25 to 33 times your first-year spending at FI**: 25 times is the classic "4% rule" for a 30-year retirement, and a longer early retirement needs nearer 28 to 33 times. For example, £3,500 a month today is about £65,400 a year in 15 years at 3% inflation, so a FIRE number of roughly £1.6 to 2.2 million across ISAs, pensions and other savings. The State Pension, about £12,550 a year at the full rate, brings the later years' cost down.

## How many times your spending do you need?

Divide 100 by the share of your money you plan to withdraw in the first year: at 4% that is 25 times your yearly spending. A lower withdrawal rate needs a bigger FIRE number but leaves more margin for a long retirement or a bad start.

| Withdrawal rate | Multiple needed | On £65,400 a year |
| --- | --- | --- |
| 4% | 25× | £1.64 million |
| 3.5% | 28.6× | £1.87 million |
| 3.25% | 30.8× | £2.01 million |
| 3% | 33.3× | £2.18 million |

The 4% rule comes from US market history for 30-year retirements. For a retirement of 40 years or more, 3 to 3.5% is common. Read [Is the 4% rule safe for early retirement?](https://mywealthcheck.com/blog/4-percent-rule/) for why.

## The three-phase plan: ISAs, pensions, State Pension

- **From your FI age to 57: ISAs and other savings.** A Stocks & Shares ISA can be drawn at any age, tax-free. Retiring at 45 needs 12 years of spending here.
- **From 57: your pensions.** Workplace pensions and SIPPs open at the normal minimum pension age (57 for anyone born on or after 6 April 1973), with 25% tax-free.
- **From 67 or 68: the State Pension.** It pays for life and rises every year, so your own savings have less to cover from then on.

The quick calculator above treats your savings as one pot, so it answers "how much in total". The [full planner](https://mywealthcheck.com/planner/) keeps your pension locked until 57, adds the State Pension as income and tells you whether your ISAs last until then.

## How this FIRE calculator works

1. **Your spending at FI.** Today's monthly spending grows with inflation until your FI age. That gives your first-year spending after you stop working.
2. **Your FIRE number.** We add up every year's spending from your FI age to your plan age, still rising with inflation. Each year's money is assumed to stay invested until it's needed: the next 10 years in bonds and cash, later years in a mix with more stocks. The total is what you need on day one.
3. **What you already have.** Your current investments, in ISAs, pensions and general accounts, grow at the returns you enter. Whatever's left is the gap your monthly investing has to fill.
4. **Monthly investment.** We find the first-year monthly amount, including your employer's pension contribution, that closes the gap, rising by your yearly increase, with stocks reduced gradually as FI gets closer.
5. **Will it last?** We simulate the FIRE number year by year after FI, at expected returns and after a 35% stock crash in the first year.

## How is FIRE different in the UK?

- **Pensions are locked until 57.** They are still the best deal for most people, thanks to tax relief and employer contributions, but they can't fund the first years of an early retirement.
- **ISAs are the bridge.** £20,000 a year each, tax-free in and out. A couple can shelter £40,000 a year.
- **Healthcare is free at the point of use.** The NHS doesn't depend on your job, so there is no gap to fill as in the US.
- **The State Pension needs National Insurance years.** Stopping work early can leave you short of the 35 years for the full rate. Check your forecast and consider voluntary contributions.
- **Pensions and inheritance tax.** From 6 April 2027 most unused pensions count towards your estate for inheritance tax, which may change how fast you choose to draw on them. Rules as of November 2026.
- **Sequence risk.** A market crash in the first few years after you stop working does the most damage. Keeping several years of spending in bonds and cash (a bucket strategy) avoids selling stocks at a low.

## Frequently asked questions

### How much money do I need to retire early in the UK?

Usually about 25 to 33 times your yearly spending at the age you stop working, split between ISAs and other savings that pay for the years before you can take your pension, and pensions that take over after that. Start with what you spend today and add inflation: £3,500 a month today becomes about £65,400 a year in 15 years at 3% inflation, so a FIRE number of roughly £1.6 to 2.2 million in total. The State Pension lowers what you need from 67 or 68. This calculator works out the exact number year by year for your inputs.

### When can I take money from my pension?

From the normal minimum pension age, which is 55 today and rises to 57 on 6 April 2028. If you were born on or after 6 April 1973 you will be 57 before you can take a workplace pension or SIPP, unless your scheme gives you a protected pension age. You can usually take 25% tax-free, up to the lump sum allowance of £268,275 in total; the rest is taxed as income when you draw it. The State Pension is separate and starts later.

### Should I use an ISA or a pension to retire early?

Usually both. ISAs pay for the bridge: money comes out tax-free at any age, and you can put in up to £20,000 a year (from 6 April 2027, at most £12,000 of that can go into a cash ISA if you are under 65). Pensions get tax relief at your marginal rate and often an employer contribution, so they are the cheaper way to fund the years after 57. Work out how many years your ISAs must cover, fund that, and put the rest into your pension. This quick calculator treats everything as one pot; the full planner keeps your pension locked until 57.

### How much can I pay into a pension?

Up to £60,000 a year (the annual allowance), or 100% of your earnings if lower, including employer contributions, with unused allowance carried forward from the past three tax years. The allowance is tapered for very high incomes, and once you start taking taxable income from a defined contribution pension it falls to £10,000 a year (the money purchase annual allowance). Check the current limits on GOV.UK.

### How much State Pension will I get, and when?

The full new State Pension is £241.30 a week in 2026/27, about £12,550 a year, and it rises every April under the triple lock. You need 35 qualifying years of National Insurance for the full amount and usually at least 10 for any. State Pension age is 66, rising to 67 for people born on or after 6 March 1961, and under current law to 68 between 2044 and 2046 for people born after 5 April 1977. If you stop working early, check your forecast on GOV.UK: years you are not working or claiming credits don't count, and you may be able to fill gaps with voluntary contributions.

### How is my money taxed once I stop working?

ISA withdrawals are tax-free and don't count as income. Outside an ISA, gains above the £3,000 annual exempt amount are taxed at 18% or 24%, and dividends above the £500 allowance at 10.75% (basic rate) or 35.75% (higher rate) in 2026/27. Pension income is taxed as income after the 25% tax-free part, and the first £12,570 of your total income is covered by the personal allowance. Many early retirees keep their taxable income low by drawing from ISAs and pensions together. Enter after-tax returns in the calculator.

### Is the 4% rule safe for a UK early retirement?

The 4% rule comes from US stock and bond returns for 30-year retirements. Studies of UK market history have generally found lower safe withdrawal rates, and a retirement of 40 to 50 years needs more margin, so many UK early retirees plan on 3 to 3.5%. Instead of a fixed rule, this calculator sizes your FIRE number so a bucket strategy lasts until your plan age at the returns you enter, and shows what happens if markets crash in your first year.

### Do I need health insurance if I retire early in the UK?

No. The NHS covers you whether or not you work. Some people keep private medical insurance after leaving an employer scheme to avoid waiting lists; if you plan to, add the premium, which rises with age, to your spending. Dental and optical costs are worth budgeting for too.

### What returns and inflation should I assume?

Use long-run, after-tax returns and stay conservative. The UK defaults are 6.5% for stocks, 4% for bonds and cash, and 3% inflation. The Bank of England targets 2% inflation, but prices have risen faster than that in many years, so 3% leaves a margin. Higher return assumptions lower the monthly amount you are shown, but if real returns turn out lower you could fall short.

### Is my data stored anywhere?

No. The calculator runs in your browser and your numbers are not sent to any server. The inputs appear in the page address only so you can bookmark or share a result yourself.

## Sources

Rules and rates change. Check the current figures with the official source before acting.

- [Office for National Statistics](https://www.ons.gov.uk/economy/inflationandpriceindices): UK inflation
- [GOV.UK](https://www.gov.uk/personal-pensions-your-rights): when you can take a personal pension
- [GOV.UK](https://www.gov.uk/tax-on-your-private-pension/annual-allowance): pension annual allowance
- [GOV.UK](https://www.gov.uk/individual-savings-accounts): ISA allowance
- [GOV.UK](https://www.gov.uk/new-state-pension/what-youll-get): new State Pension rates
- [GOV.UK](https://www.gov.uk/state-pension-age): State Pension age checker
- [HMRC](https://www.gov.uk/guidance/capital-gains-tax-rates-and-allowances): capital gains tax rates and allowances
- [GOV.UK](https://www.gov.uk/tax-on-dividends): dividend allowance and tax rates
- [MoneyHelper](https://www.moneyhelper.org.uk/en/pensions-and-retirement): free government-backed pension guidance

**For education only, not financial advice.** Results depend on your inputs and on assumed returns and inflation, which will differ from reality. [How we calculate](https://mywealthcheck.com/methodology/) · [Read the disclaimer](https://mywealthcheck.com/disclaimer/).