FIRE Calculator
Financial Independence, Retire Early. Calculate exactly how much you need and how long it will take to reach full financial freedom.
Your Details
FIRE Number
£750,000
At 4% withdrawal
Years to FIRE
25 yrs
FIRE age: 55
Coast FIRE Number
£70,247
Invested today to coast
Annual Contribution
£10,000
Needed to hit target
Portfolio Projection
Assumes 7% nominal annual return. Not inflation-adjusted.
How does the FIRE calculator work?
The FIRE number is calculated using the 4% rule: multiply your desired annual income by 25. If you need £30,000/year, you need £750,000 invested. The calculator then shows how many years of saving at your stated contribution rate — assuming your chosen growth rate — it takes to reach that number.
It also shows your Coast FIRE number — the smaller milestone where you can stop contributing and let compound growth carry you the rest of the way.
FIRE variants — which is right for you?
Worked example
Scenario: Age 32, salary £55,000, current savings £40,000, saving £1,500/month, target income £35,000/year in retirement.
FIRE number: £35,000 × 25 = £875,000 (using 4% SWR)
Coast FIRE number: Assuming 7% real returns and retirement at 55 — you need around £215,000 invested today to reach £875,000 without further contributions.
Time to FIRE: At £1,500/month, approximately 19–21 years depending on investment returns.
Frequently asked questions
What is the 4% rule?
The 4% rule states that you can withdraw 4% of your portfolio in year one of retirement, then adjust for inflation each year, with a high probability of the portfolio lasting 30+ years. It comes from the Trinity Study (1998). A £750,000 portfolio supports £30,000/year withdrawals.
How much do I need to retire in the UK?
The FIRE number is your desired annual income multiplied by 25 (the inverse of 4%). For a £30,000/year retirement, you need £750,000. For £50,000/year, you need £1.25 million. The State Pension (currently ~£11,500/year) can reduce the required portfolio once you reach State Pension age.
Is a 4% withdrawal rate safe for a 40-year retirement?
Research suggests 4% has historically succeeded over 30-year periods. For longer retirements (40–50 years, common in early retirement), some financial planners recommend 3–3.5% to add a safety margin. This increases the required portfolio by 15–30% but significantly reduces failure risk.
Should I include my pension in my FIRE number?
Yes, if you plan to access it. UK pensions (SIPP, workplace) are accessible from age 57 (rising). Many FIRE planners use a two-phase strategy: bridge from early retirement to pension access using ISA and investment accounts, then supplement with pension income. Use the pension expected value to reduce your required ISA/investment portfolio.
What investment return should I use?
A real return (after inflation) of 5–7% is commonly used for long-term equity portfolios. Global equity index funds have historically returned around 7% real over long periods, though past performance doesn't guarantee future results. Using a conservative 5% real return gives a more cautious FIRE timeline.
What is the difference between FIRE and Coast FIRE?
FIRE requires a full portfolio that can support withdrawals immediately. Coast FIRE is a smaller milestone — the amount where, if you stop contributing, compound growth alone will grow the portfolio to your full FIRE number by retirement age. Coast FIRE lets you stop aggressive saving earlier and shift to lower-stress work.