How to Use FIRE Calculator
The FIRE Calculator projects your journey to Financial Independence, Retire Early by estimating your "FIRE number"—the total amount of savings required to cover your annual expenses indefinitely. It factors in your current savings, annual spending, expected investment returns, and inflation to provide a clear timeline to financial freedom.
What It Does
Use the calculator with intent
The FIRE Calculator projects your journey to Financial Independence, Retire Early by estimating your "FIRE number"—the total amount of savings required to cover your annual expenses indefinitely. It factors in your current savings, annual spending, expected investment returns, and inflation to provide a clear timeline to financial freedom.
This tool is invaluable for anyone aspiring to achieve financial independence, whether to retire decades early, pursue passion projects, or simply gain control over their time. It's particularly useful for aggressive savers, those planning career changes, or individuals curious about the viability of an early retirement strategy.
Interpreting Results
Start with Target Portfolio. Then compare Lean Target Portfolio and Fat Target Portfolio before deciding what changes the answer most.
Input Steps
Field by field
- 1
Current Age + Current Portfolio
Enter current age, portfolio value, annual spending, annual savings, expected return, inflation, and withdrawal rate using after-tax spending. Annual spending is the most important input because it determines the size of the portfolio you are trying to replace.
- 2
Annual Spending + Annual Savings
Read the target portfolio and years to financial independence first, then compare lean, standard, and fat targets. A 4% withdrawal rate implies a target near 25x annual spending, while 3.5% implies about 29x.
- 3
Expected Return Percent + Volatility Percent
Every additional $10,000 of annual spending changes a 4% FIRE target by about $250,000. If your savings rate is below roughly 20%, the timeline will usually move much more from spending cuts than from optimistic return assumptions.
- 4
Inflation Percent + Withdrawal Rate Percent
Test 3.5%, 4%, and 4.5% withdrawal rates, then decide whether the safer path is lower spending, higher savings, or a later date. Follow with the retirement calculator if you need a more traditional retirement view.
- 5
Horizon Years
Re-run yearly, after a 10%+ portfolio move, or when annual spending changes by more than 5%. Track savings rate, annual spending, and years-to-FI rather than only the portfolio balance.
- 6
Setup
Enter setup with realistic baseline assumptions before moving to sensitivity checks.
Run one base case and one sensitivity case before trusting a single output.
Common Scenarios
Use realistic starting points
Baseline assumptions
Current Age
$34
Current Portfolio
$180,000
Annual Spending
$52,000
Annual Savings
$24,000
Start with target portfolio and compare it with lean target portfolio before changing anything.
Higher Current Age
Current Age
$40.80
Current Portfolio
$180,000
Annual Spending
$52,000
Annual Savings
$24,000
Watch how target portfolio shifts when current age changes while the rest stays steady.
Lower Current Portfolio
Current Age
$34
Current Portfolio
$153,000
Annual Spending
$52,000
Annual Savings
$24,000
Watch how target portfolio shifts when current portfolio changes while the rest stays steady.
Try These Tools
Run the numbers next
FAQ
Questions people ask next
The short answers readers usually want after the first pass.
Sources & References
- The Trinity Study: Retirement Spending: Can I Afford to Retire? — AAII Journal (American Association of Individual Investors)
- Your Money or Your Life — Penguin Random House
Related Content
Keep the topic connected
What Is FIRE? Simply Explained
Achieve financial independence and retire early (FIRE) by aggressively saving and investing to cover all living expenses with passive income.
What Is Coast FIRE? Simply Explained
Discover Coast FIRE: save enough early to let investments grow passively, enabling an earlier, less stressful path to financial independence. Learn how to calculate your number.
What Is Sequence of Returns Risk? Simply Explained
Understand Sequence of Returns Risk: how the timing of market returns impacts your retirement savings, especially during withdrawal phases. Learn to mitigate it.