FIRE Calculator

Financial Independence, Retire Early commonly known as FIRE is a movement built on aggressive saving and disciplined investing to reach a point where work becomes optional. At the heart of FIRE is a simple calculation: divide your annual retirement expenses by a safe withdrawal rate to determine the portfolio size you need. This FIRE Calculator turns that formula into a complete projection. It accounts for your current assets, monthly contributions, real investment return after inflation, and the lifestyle you want in retirement. You’ll see your FIRE number, the years remaining, your FIRE age, and a year-by-year growth table. The tool supports 22 currencies and three FIRE variants, Lean, Regular, and Fat, so you can model different retirement lifestyles. All calculations run in your browser, keeping your financial data private.

How to Use the FIRE Calculator

1. Select your currency from the dropdown menu.

2. Enter your current age.

3. Input your current invested assets.

4. Enter your monthly investment amount.

5. Provide your expected monthly retirement expenses in today’s dollars.

6. Choose your FIRE lifestyle: Lean, Regular, or Fat FIRE.

7. Set your expected annual return and inflation rate.

8. Adjust the safe withdrawal rate if desired, using the SWR guide for reference.

9. Click Calculate to view your FIRE number, years to FIRE, and FIRE age.

10. Review the FIRE number breakdown and progress bar.

11. Check the FIRE variants section for Lean, Regular, and Fat FIRE targets.

12. Review the progress milestones and year-by-year projection table.

13. Use the quick example buttons to test Lean, Regular, Fat, Coast, and Barista FIRE scenarios.

14. Copy, share, or embed your results using the buttons below.

How the FIRE Calculator Formula Works

The FIRE Calculator combines several well-established financial formulas.

FIRE Number:
FIRE Number = Annual Retirement Expenses ÷ Safe Withdrawal Rate

Annual Retirement Expenses:
Annual Expenses = Monthly Retirement Expenses × 12 × FIRE Multiplier
Where the FIRE multiplier is 0.7 for Lean FIRE, 1.0 for Regular FIRE, and 1.5 for Fat FIRE.

Real Return (after inflation):
Real Return = ((1 + Expected Return) ÷ (1 + Inflation)) − 1

Monthly Compounding:
Monthly Real Return = Real Return ÷ 12

Portfolio Growth:
Portfolio(t+1) = Portfolio(t) × (1 + Monthly Real Return) + Monthly Investment

The calculator iterates month by month until the portfolio reaches the FIRE number or the 80-year cap is reached. It reports progress as current assets divided by the FIRE number, and computes FIRE age by adding years to FIRE to the current age.

FIRE Variants:

• Lean FIRE: 70% of your estimated expenses

• Regular FIRE: 100% of your estimated expenses

• Fat FIRE: 150% of your estimated expenses

Interpretation:

• Already Financially Independent: Assets ≥ FIRE number

• Fast Track: ≤ 10 years

• On Track: 11–20 years

• Moderate: 21–30 years

• Slow Track: > 30 years

• Unreachable: No projection within 80 years

Worked Example

Consider a 30-year-old with $50,000 invested, saving $1,500 per month, expecting $3,500 in monthly retirement expenses, a 7% annual return, 3% inflation, a 4% safe withdrawal rate, and a Regular FIRE lifestyle.

Step 1 – Annual retirement expenses:
$3,500 × 12 × 1.0 = **$42,000**

Step 2 – FIRE number:
$42,000 ÷ 0.04 = **$1,050,000**

Step 3 – Real return:
((1 + 0.07) ÷ (1 + 0.03)) − 1 = 0.03883 → 3.88%

Step 4 – Monthly real return:
3.88% ÷ 12 = 0.3236%

Step 5 – Time to FIRE:
Starting at $50,000 and adding $1,500 per month at 0.3236% monthly real return, the portfolio reaches $1,050,000 in approximately 262 months, or 21.8 years.

Step 6 – FIRE age:
30 + 21.8 = 51.8 years old

Step 7 – Classification:
21.8 years falls in the Moderate Timeline (21–30 years).

Interpretation:
“Target: Regular FIRE with $42,000 annual expenses. FIRE Number: $1,050,000. Current portfolio: $50,000 (4.8% of goal). Years to FIRE: 21.8 at age 52. Consider increasing your savings rate significantly to shorten the timeline.”