What is the FIRE Burn Rate Calculator?
The FIRE Burn Rate Calculator helps you understand how your annual spending directly affects your FIRE number and how quickly you can reach financial independence. By tracking your real spending and linking it to your investments and pensions, it shows how small changes in your burn rate can materially shorten your FIRE timeline.
How the Calculator Works?
This calculator starts with your monthly income, spending and investment balances to calculate your annual burn rate and corresponding FIRE number. It then projects how your portfolio grows over time using UK-specific accounts such as ISAs, GIAs and pensions, while accounting for pension access ages and the bridge period before pensions become available.
You can log actual monthly spending over time, allowing the calculator to replace estimates with real averages. This makes your FIRE number more accurate and highlights how changes in spending behaviour affect your long-term plan.
Step One: Enter Your Baseline Finances
Add your monthly income, spending, portfolio balances and contributions across cash, ISAs, GIAs and pensions. Set your age, pension access age, State Pension age, expected returns and withdrawal rate.
Step Two: Track and Refine Your Burn Rate
Log your actual monthly income and spending. The calculator uses rolling averages to refine your burn rate and highlight trends, volatility and one-off expenses.
Step Three: Review Your FIRE Progress and Timeline
See your FIRE number, savings rate, progress so far and estimated FIRE age. Test how reducing spending by 5%, 10% or 15% affects your FIRE number and retirement date.
FIRE Burn Rate Calculator
Step 1: Monthly income and spending
Step 2: Portfolio and contributions
Step 3: Assumptions
| Month | Income | Spend | Saved | Savings rate | Notes |
|---|
Disclaimer:
This calculator provides illustrative projections only and does not constitute financial advice. Investment returns, spending patterns and pension rules may change. Consider speaking with a qualified financial adviser before making major retirement decisions.
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What is the FIRE Burn Rate Calculator?
It is a UK-focused FIRE planning tool that links real spending data to your FIRE number and timeline, showing how changes in your burn rate affect how soon you can reach financial independence..
What is a burn rate in FIRE planning?
Your burn rate is your annual spending. It is the single most important input for calculating your FIRE number, as it determines how much income your portfolio needs to support.
Why does reducing spending matter so much?
Reducing spending lowers your FIRE number directly. A 10% cut in spending reduces the amount of wealth you need by the same proportion, often having a bigger impact than trying to earn more.
How does monthly tracking improve accuracy?
Logging real spending replaces assumptions with actual data. Over time, this produces a more realistic burn rate and highlights lifestyle inflation or volatility that may affect your plan.
Does the calculator include UK pension rules?
Yes. It models pension access ages and separates accessible investments from pension pots to ensure the bridge period is handled correctly.
Does the calculator include UK pension rules?
Yes. It models pension access ages (default 57 unless changed) and separates pre- and post-pension income correctly.
What withdrawal rates can I test?
You can view FIRE numbers across multiple withdrawal rates, including 3%, 4%, 5% and 6%, to understand the trade-offs between risk and required wealth.
What is spending volatility and why does it matter?
High volatility means your spending varies significantly month to month. This can make early retirement riskier, as large unexpected expenses may strain your portfolio.
Does it warn me if my bridge is too small?
Yes. The calculator flags when your accessible investments may not be sufficient to cover spending until pension access age.
Can I export my data?
Yes. You can export and import your data using CSV or JSON files for backup or analysis.
Is my data stored?
No. All calculations run locally in your browser.
Is this a replacement for financial advice?
No. It is a planning and tracking tool designed to support better decisions, not replace professional advice.