FIRE Number Calculator
How much do you need to retire early?
Calculate your Financial Independence, Retire Early (FIRE) number based on your planned spending and safe withdrawal rate. Models your year-by-year path to FI, including the UK State Pension offset.
Annual spending in retirement
How much you plan to spend per year in today's money
FIRE variant
Standard FIRE: 100% of your spending
State Pension
Include State Pension offset
Reduces your FIRE number when SP starts paying
Safe withdrawal rate
The 4% rule is common but UK historical data supports 3.5–4% more robustly
Current position
Total investable assets (ISA, SIPP, GIA etc.)
Target age (optional)
Set a target FIRE age
Calculates the savings rate needed to hit that date
Growth & savings assumptions
Nominal return before inflation. Global equities ~7–9% historically
Used to show real (inflation-adjusted) portfolio value
New money added to your portfolio each year
Your FIRE number
£750,000
£30,000 annual spend ÷ 4.0% SWR
Shortfall: £700,000
Time to FIRE
22 years
In 2048
Projected FIRE age
Age 57
Portfolio growth to FIRE
| Label | Value |
|---|---|
| FIRE number | £750,000 |
| Time to FIRE | 22 years |
| Projected FIRE age | Age 57 |
FIRE reached at age 57 (2048). The green line shows purchasing power in today's money.
FIRE variant comparison
| Variant | Annual spend | FIRE number | Years to FIRE | FIRE age |
|---|---|---|---|---|
| lean | £22,500 | £562,500 | 18y | Age 53 |
| standard | £30,000 | £750,000 | 22y | Age 57 |
| fat | £45,000 | £1,125,000 | 27y | Age 62 |
Withdrawal rate sensitivity
How different SWRs affect your FIRE number and timeline
| Withdrawal rate | FIRE number | Years to FIRE |
|---|---|---|
| 3.0% | £1,000,000 | 25y |
| 3.5% | £857,143 | 23y |
| 4.0%← current | £750,000 | 22y |
| 4.5% | £666,667 | 20y |
| 5.0% | £600,000 | 19y |
Year-by-year projection
| Year | Age | Opening | Growth | Savings | Closing | Progress |
|---|---|---|---|---|---|---|
| 2026 | 35 | £50,000 | +£3,500 | +£12,000 | £65,500 | 8.7% |
| 2027 | 36 | £65,500 | +£4,585 | +£12,000 | £82,085 | 10.9% |
| 2028 | 37 | £82,085 | +£5,746 | +£12,000 | £99,831 | 13.3% |
| 2029 | 38 | £99,831 | +£6,988 | +£12,000 | £118,819 | 15.8% |
| 2030 | 39 | £118,819 | +£8,317 | +£12,000 | £139,136 | 18.6% |
| 2031 | 40 | £139,136 | +£9,740 | +£12,000 | £160,876 | 21.5% |
| 2032 | 41 | £160,876 | +£11,261 | +£12,000 | £184,137 | 24.6% |
| 2033 | 42 | £184,137 | +£12,890 | +£12,000 | £209,027 | 27.9% |
| 2034 | 43 | £209,027 | +£14,632 | +£12,000 | £235,659 | 31.4% |
| 2035 | 44 | £235,659 | +£16,496 | +£12,000 | £264,155 | 35.2% |
| 2036 | 45 | £264,155 | +£18,491 | +£12,000 | £294,646 | 39.3% |
| 2037 | 46 | £294,646 | +£20,625 | +£12,000 | £327,271 | 43.6% |
| 2038 | 47 | £327,271 | +£22,909 | +£12,000 | £362,180 | 48.3% |
| 2039 | 48 | £362,180 | +£25,353 | +£12,000 | £399,533 | 53.3% |
| 2040 | 49 | £399,533 | +£27,967 | +£12,000 | £439,500 | 58.6% |
| 2041 | 50 | £439,500 | +£30,765 | +£12,000 | £482,265 | 64.3% |
| 2042 | 51 | £482,265 | +£33,759 | +£12,000 | £528,023 | 70.4% |
| 2043 | 52 | £528,023 | +£36,962 | +£12,000 | £576,985 | 76.9% |
| 2044 | 53 | £576,985 | +£40,389 | +£12,000 | £629,374 | 83.9% |
| 2045 | 54 | £629,374 | +£44,056 | +£12,000 | £685,430 | 91.4% |
| 2046 | 55 | £685,430 | +£47,980 | +£12,000 | £745,410 | 99.4% |
| 2047✓ FIRE | 56 | £745,410 | +£52,179 | +£12,000 | £809,589 | 100.0% |
| 2048 | 57 | £809,589 | +£56,671 | +£12,000 | £878,260 | 100.0% |
Model your full retirement plan
The FIRE number gives you a target. The Selvox retirement calculator runs 10,000 Monte Carlo simulations using 125 years of UK market data to stress-test your plan against real-world sequence-of-returns risk.
Open retirement calculator →Want a complete retirement projection?
For a complete retirement projection including tax, State Pension, and 10,000 Monte Carlo simulations — use our full retirement planner.
This calculator provides estimates for guidance only. Results are illustrative and do not constitute financial advice. Always verify figures with a qualified adviser.