FIRE Number Calculator

Annual Spending in Retirement ($)

Safe Withdrawal Rate — 4.0%

Conservative 3%Aggressive 5%

Expected Annual Return

Current Portfolio Value ($)

Monthly Savings ($)

Your FIRE Number

—

Years to FIRE

—

Monthly Savings Needed

—

Progress to FIRE0%

Path to Financial Independence

Understanding Your FIRE Number

What Is the 4% Rule and How Does It Define Your FIRE Number?

Your FIRE number is the total amount of investment assets you need to be financially independent — meaning you can live indefinitely off your investments without ever needing to work again. It's derived from the 4% rule, which comes from the landmark Trinity Study conducted by researchers at Trinity University in 1998.

The study found that a diversified portfolio of stocks and bonds could sustain a 4% annual withdrawal rate for at least 30 years in 95%+ of historical scenarios. To calculate your FIRE number, divide your expected annual spending by 0.04 (or multiply by 25). Need $50,000/year? Your FIRE number is $1,250,000.

FIRE vs Coast FIRE: What's the Difference?

Your full FIRE number represents the portfolio value you need to stop working entirely. Your Coast FIRE number is a smaller, earlier milestone: the amount you need invested today so that compound growth alone will reach your FIRE number by retirement age — without any additional contributions. Our Coast FIRE Calculator on the homepage calculates your Coast FIRE number if you haven't used it yet.

Lean FIRE vs Fat FIRE

Lean FIRE typically involves living on $40,000/year or less, meaning a FIRE number of $1,000,000 or under. It requires significant frugality but is achievable faster. Fat FIRE targets $100,000+/year in retirement spending, translating to a $2.5 million+ FIRE number. Barista FIRE and Coast FIRE sit in the middle, combining partial work income with a smaller portfolio.

How Safe Withdrawal Rate Affects Your Number

The withdrawal rate slider in the calculator above dramatically changes your FIRE number. At 3% (very conservative), your FIRE number is 33x your annual spending. At 4% (the standard), it's 25x. At 5% (aggressive), it's only 20x. Many early retirees who plan for a 40-50 year retirement use 3-3.5% to build in extra margin against sequence-of-returns risk, where a market downturn in your first years of retirement can permanently impair your portfolio.

Strategies to Reach FIRE Faster

The most powerful lever for reaching FIRE faster is your savings rate. Someone saving 50% of their income can reach FIRE in approximately 17 years, regardless of their income level. At 25%, it takes about 32 years. At 75%, just 7 years. Reducing expenses is doubly powerful: it lowers your required FIRE number (you need to spend less in retirement too) while simultaneously increasing your savings rate.

Investment strategy matters as well. Low-cost index funds tracking the total US market or S&P 500 have historically outperformed the vast majority of actively managed funds over 15+ year periods, after fees. The difference between a 0.05% expense ratio and a 1% expense ratio over 25 years can represent hundreds of thousands of dollars in your final portfolio.

Frequently Asked Questions

Your FIRE number is the total investment portfolio value you need to be financially independent — meaning your investments generate enough passive income to cover all your living expenses indefinitely. It's typically calculated as 25x your annual spending (using the 4% rule), though more conservative estimates use 28-33x (3-3.5% withdrawal rate) for longer retirement horizons.

The 4% rule remains the most widely cited starting point for retirement withdrawal planning, though some researchers argue for lower rates (3-3.5%) given current market valuations and longer life expectancies. For a 30-year retirement, 4% has historically been very robust. For a 40-50 year retirement (common for early retirees), using 3-3.5% provides more margin. The right rate depends on your specific circumstances, flexibility to adjust spending, and other income sources.

Time to FIRE depends entirely on your savings rate. At a 10% savings rate, it takes approximately 40 years. At 25%, about 32 years. At 50%, roughly 17 years. At 75%, as little as 7 years. The key insight is that your savings rate matters far more than your income. Two people with very different incomes but the same savings rate will reach FIRE at the same time (in terms of years, not absolute dollar amounts).

Generally, no. Your primary residence typically doesn't generate investment income and isn't liquid in the traditional sense. Most FIRE practitioners only count liquid, investable assets — stock accounts, bonds, index funds, REITs — in their FIRE number calculation. Real estate rental income can be included if you own rental properties, as that generates cash flow. However, if you plan to downsize your home at retirement and invest the proceeds, you can factor that in separately.

Lean FIRE: retiring with minimal spending, typically under $40k/year. Requires the smallest portfolio. Fat FIRE: retiring with a high lifestyle, typically $100k+/year spending, requiring $2.5M+. Coast FIRE: having enough invested that compound growth alone will reach your FIRE number by a traditional retirement age — you still work but only to cover current expenses. Barista FIRE: retiring from a high-stress career but doing part-time work to cover living expenses while your portfolio continues growing. Each variant suits different risk tolerances and lifestyle preferences.