This free FIRE calculator estimates three things that matter for anyone pursuing Financial Independence, Retire Early: your FIRE number, your savings rate, and the number of years until your investments can cover your living costs. Enter your income, annual spending, current savings, and expected return — drag the sliders or type exact figures — and the projection updates instantly, all computed privately in your browser.
Your FIRE number is the amount invested that lets portfolio returns cover your expenses indefinitely. It is calculated as 25 times your annual spending — the inverse of the 4% safe withdrawal rate:
FIRE Number = Annual Spending × 25
Spend $40,000 a year and your number is $1,000,000; spend $60,000 and it is $1,500,000. Notice that spending drives everything: cutting your annual spending by $10,000 removes $250,000 from the target and frees up $10,000 more to invest each year. That double effect is why frugality is such a powerful FIRE lever.
The single biggest factor in your timeline is your savings rate — the share of take-home income you invest. Because a higher savings rate both grows contributions and shrinks the target, the relationship is dramatic:
| Savings rate | Approx. years to FIRE |
|---|---|
| 10% | ~51 years |
| 25% | ~32 years |
| 50% | ~17 years |
| 65% | ~10.5 years |
| 75% | ~7 years |
These assume a 5% real return and starting from zero. The lesson: income helps, but the percentage you keep is what sets your freedom date.
Suppose you earn $80,000 net, spend $50,000, and have $30,000 invested. Your savings rate is ($80k − $50k) / $80k = 37.5%. Your FIRE number is $50,000 × 25 = $1,250,000. At a 5% real return, investing $30,000 a year gets you there in roughly 20 years. Bump spending down to $42,000 and two things happen at once: the target drops to $1,050,000 and annual savings rise to $38,000 — shaving several years off the timeline.
FIRE is a spectrum, and this calculator can model each variant:
The 4% rule was studied for 30-year retirements. If you plan to retire at 40 and may need the portfolio to last 50+ years, many practitioners use a more conservative 3.5% withdrawal rate — equivalent to targeting about 28.6× annual spending. To approximate this here, nudge your spending input up slightly so the calculator aims a little higher.
What savings rate do I need to retire in 10 years? Roughly 65% of take-home income, assuming a 5% real return and starting near zero. Existing savings shorten that considerably.
Does this FIRE calculator work for couples? Yes. Combine both incomes and use a single shared annual-spending figure; combined saving usually produces a much shorter timeline than either person alone.
Is my data private? Completely. All maths runs in your browser; your income and savings are never sent anywhere.
New to the concept? Start with What Is FIRE? and The 4% Rule Explained.
This tool is Step 6 of our master guide — The DIY Financial Plan: From First Dollar to Financial Independence.
Explore our other tools — Retirement Calculator, Mortgage Calculator, and Portfolio Stress-Tester. WealthDeck provides educational tools only, not financial advice — see our Terms & Disclaimer.