FIRE Calculator
FIRE Variants
| Target | Years | |
|---|---|---|
| Lean FIRE (60%) | $750K | 13.3 |
| Regular FIRE | $1.3M | 18.5 |
| Fat FIRE (150%) | $1.9M | 23.2 |
What Is FIRE?
FIRE — Financial Independence, Retire Early — rests on one equation: save aggressively, invest for growth, and build a portfolio whose withdrawals cover living expenses indefinitely. Your FIRE number is annual expenses divided by your safe withdrawal rate. At 4%, that's 25 times annual spending. Enter your income, expenses, and portfolio above to see your target, years to FIRE, Coast FIRE milestone, and Lean/Regular/Fat timelines update in real time.
The movement isn't about deprivation. It's about reaching the crossover point where investment income exceeds expenses, giving you the freedom to work on your own terms — or not at all.
Why Savings Rate Matters More Than Income
Savings rate is the strongest lever in the FIRE equation — stronger than income alone. At 10% savings, FIRE takes roughly 50 years. At 50%, about 17 years. At 75%, around 7 years. Want FIRE in 10 years? You typically need a savings rate above 65%. Each extra percentage point grows your portfolio faster and lowers your FIRE number, because lower spending means a smaller target.
This is why a $60,000 earner saving 60% can reach FIRE faster than a $200,000 earner saving 10%. Income matters, but the ratio of saving to spending is what determines the timeline.
The 4% Rule: What It Really Means
The 4% rule comes from the 1998 Trinity Study, which found that a balanced portfolio (stocks + bonds) survived 30 years in 95% of historical periods at a 4% initial withdrawal rate, adjusted for inflation each year after. For early retirees with 40-60 year horizons, a more conservative 3.25-3.5% rate provides additional safety margin.
The rule isn't a guarantee — it's a historically tested guideline. Flexible spending (reducing withdrawals 10-20% during bear markets) and maintaining some earned income in early retirement dramatically improve portfolio survival rates. Once you've reached your FIRE number, use our Retirement Withdrawal Calculator to plan your sustainable withdrawal strategy.
Coast FIRE: The Halfway Milestone
Coast FIRE is the point where your current portfolio will grow to your full FIRE number by age 65 through compound returns alone — no more contributions needed. After Coast FIRE, you only need income to cover today's expenses, not to save for retirement. That opens the door to part-time work, career changes, or lower-stress jobs years before full FIRE.
For many people, Coast FIRE is the more achievable first target. It removes the pressure of constant saving and provides a psychological safety net years before full FIRE.
Lean, Regular & Fat FIRE: Three Targets, One Timeline
Not everyone needs — or wants — the same retirement lifestyle. Lean FIRE targets 60% of your current expenses (a more frugal post-work life), Regular FIRE matches your current spending, and Fat FIRE targets 150% (more travel, hobbies, or a larger safety buffer). The calculator above shows all three target amounts and timelines side by side, using your actual numbers.
The key insight: Lean FIRE is often reachable 7-10 years before Fat FIRE. Many people use Lean FIRE as an "escape hatch" — the point where work becomes optional at a modest lifestyle — while continuing to save toward Regular or Fat. Seeing all three on a single screen helps you set realistic milestones instead of fixating on one distant number.
Cutting Expenses Accelerates FIRE Twice
Reducing spending is the most powerful lever in the FIRE equation because it pushes both sides simultaneously. Cut $500 per month ($6,000 per year) and two things happen: your FIRE number drops by $150,000 (at a 4% withdrawal rate) AND your annual savings increase by $6,000. Together, these can shave 3-5 years off your timeline — far more than you'd expect from a "small" lifestyle change.
This double acceleration is why FIRE practitioners obsess over spending rather than income. A $6,000 raise helps once (more savings). A $6,000 expense cut helps twice (more savings AND a lower target). The narrative summary below the chart quantifies this effect for your exact inputs. To see how your savings compound over time, explore our Compound Interest Calculator.
Frequently Asked Questions
- What is the FIRE movement and how does the FIRE number work?
- FIRE (Financial Independence, Retire Early) is a strategy focused on saving and investing enough that your investment returns cover your living expenses permanently. Your FIRE number is calculated as annual expenses divided by your safe withdrawal rate — at a 4% rate, that's 25 times your annual spending. Once your portfolio reaches this amount, you can withdraw 4% per year (adjusted for inflation) with high historical probability of the money lasting 30+ years.
- How do I calculate my FIRE number?
- Divide your annual expenses by your safe withdrawal rate. At the standard 4% rate: $50,000 annual expenses / 0.04 = $1,250,000 FIRE number. For early retirees expecting 40-60 year retirements, using a 3.25% withdrawal rate is safer: $50,000 / 0.0325 = $1,538,462. Reducing expenses has a double effect — it lowers your FIRE number AND increases how much you save each year.
- What is the 4% rule and is it safe for early retirees?
- The 4% rule comes from the Trinity Study, which tested historical stock/bond portfolios over 30-year periods. It found that withdrawing 4% in year one (adjusting for inflation thereafter) succeeded roughly 95% of the time. For early retirees with longer time horizons (40-60 years), a 3.25-3.5% rate provides more safety. Flexible spending and part-time income further improve success rates.
- What is Coast FIRE and how is it different from regular FIRE?
- Coast FIRE means your current investments will grow to your full FIRE number by age 65 through compound interest alone — without any additional contributions. At that point, you only need to earn enough to cover today's expenses. Regular FIRE means your portfolio already covers all expenses through withdrawals. Coast FIRE is typically reached years earlier and gives you the freedom to reduce work hours or change careers.
- What savings rate do I need to retire in 10 years?
- Roughly 65% or higher, assuming a 7% real return and starting from zero. At 50% savings rate, expect about 17 years to FIRE; at 25%, about 32 years; at 75%, around 7 years. The relationship is non-linear because higher savings rates both increase what you invest and reduce your target number. Even a 5-percentage-point bump — say from 40% to 45% — can cut 2–3 years off your timeline.
- How does a 3.5% withdrawal rate change my FIRE number versus 4%?
- At 4%, you need 25× annual expenses. At 3.5%, about 28.6× — roughly 15% more capital. For $50,000 in annual spending: $1,250,000 at 4% versus $1,428,571 at 3.5%. Early retirees with 40–60 year horizons often choose 3.25–3.5% for extra safety. Switch the withdrawal rate in the calculator above to see how each FIRE variant timeline shifts instantly.
- How does cutting $500 per month from expenses accelerate my FIRE date?
- Cutting $500 per month ($6,000 per year) works two ways simultaneously. First, your FIRE number drops by $150,000 (at 4% withdrawal rate, that's $6,000 / 0.04). Second, your annual savings increase by $6,000, which grows via compound interest. Combined, someone with $80,000 income and $50,000 expenses could reach FIRE 3-5 years sooner — a disproportionately large effect from a relatively small change. The calculator above shows this exact acceleration in the narrative summary.
- How much will $500 per month in savings grow toward early retirement?
- $500 per month ($6,000 per year) invested at 7% grows to about $520,000 over 30 years — and that's before the double effect of expense cuts. If that $500 per month comes from reduced spending rather than extra income, your FIRE number also drops by $150,000 (at a 4% withdrawal rate). Combined, $500 per month in expense reduction can shave 3–5 years off your FIRE date. The narrative summary below the chart quantifies this for your exact inputs.