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FIRE Calculator
Find your financial independence number and how long it will take to get there.
FIRE Number
Your target portfolio based on expenses and withdrawal rate
Savings Rate Analysis
See your savings rate and how it affects your timeline
Coast FIRE
The amount needed today to coast to retirement without saving
Calculate Your FIRE Number
Enter your income, expenses, and savings to find out when you can achieve financial independence.
How to Calculate Your FIRE Number
The FIRE Formula
FIRE Number = Annual Expenses / SWR
Savings Rate = (Income - Expenses) / Income
Your FIRE number is the portfolio size you need so that your safe withdrawal rate covers your annual expenses. A 4% withdrawal rate means you need 25x your annual expenses saved. A 3.5% rate means roughly 29x.
Worked Example
You earn £50,000 and spend £30,000 per year. Your savings rate is 40%. With a 4% safe withdrawal rate, your FIRE number is £30,000 / 0.04 = £750,000. Starting with £20,000 saved and a 7% annual return, you would reach FIRE in approximately 18 years.
Types of FIRE
Lean FIRE & Barista FIRE
Lean FIRE means reaching financial independence on a minimal budget, typically under £25,000/year in expenses. It requires a smaller portfolio but leaves less room for lifestyle inflation. Barista FIRE means having enough savings to cover most expenses, but working a low-stress part-time job to fill the gap and maintain benefits.
Fat FIRE & Coast FIRE
Fat FIRE targets a more comfortable lifestyle, typically £50,000+ per year in retirement spending. The trade-off is a much larger portfolio and longer accumulation phase. Coast FIRE is reached when your current investments will compound to your FIRE number by retirement age without further contributions.
How to Use This FIRE Calculator
Enter Your Finances
Input your age, annual income, expenses, and current savings.
Set Your Assumptions
Adjust expected return and safe withdrawal rate for your scenario.
Review Your Results
See your FIRE number, timeline, savings rate, and Coast FIRE target.
Accelerating Your Path to FIRE
- Increase your savings rate. Every percentage point increase in savings rate reduces your time to FIRE. Moving from 30% to 50% can cut your timeline nearly in half.
- Reduce your largest expenses. Housing, transport, and food typically account for 60-70% of spending. Optimising these categories has the biggest impact on your savings rate and FIRE number simultaneously.
- Grow your income. Side income, career progression, or skill development can accelerate savings without requiring lifestyle cuts. Direct all income increases to savings to avoid lifestyle inflation.
- Invest tax-efficiently. Maximise ISA allowances (£20,000/year tax-free growth), employer pension matching, and salary sacrifice. Tax savings compound alongside investment returns.
Track your path to FIRE
ARIA tracks your real portfolio performance with risk-adjusted metrics, sector analysis, and optimisation tools to help you reach financial independence faster.
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