The 4% rule states that you can withdraw 4% of your portfolio in year one of retirement, then adjust for inflation each year, and historically your portfolio will last 30+ years. It comes from the Trinity Study published in 1998.

What is a FIRE number?

Your FIRE number is the portfolio size you need to retire. It is calculated as: Annual expenses / Safe withdrawal rate. At a 4% SWR, you need 25x your annual expenses.

What annual return should I use?

The US stock market has returned roughly 10% nominally and 7% after inflation historically. For conservative planning use 6-7% real return. Adjust down if you hold bonds or other assets.

What is lean FIRE vs fat FIRE?

Lean FIRE means retiring on a minimal budget (under $40,000/year). Fat FIRE means retiring with a larger income (over $100,000/year). Regular FIRE typically targets $40,000-$80,000/year.

Does this account for taxes?

The calculator shows pre-tax projections. In reality, withdrawals from tax-deferred accounts like 401k are taxed. Factor in a 10-20% tax rate when setting your annual expenses.

F.I.R.E.

True Time to Retirement

Factor in your savings, contributions, market return and inflation to find your real FIRE number and retirement date.

Current age

Current savings (USD)

Monthly contribution (USD)

Expected annual return 7%

1%15%

Annual inflation 3%

1%10%

Annual expenses in retirement (USD)

Safe withdrawal rate 4%

2%6%

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FIRE stands for Financial Independence, Retire Early. The movement is built around one core idea: save and invest aggressively until your portfolio generates enough passive income to cover all your expenses — then you never have to work again.

The foundation of FIRE is the 4% rule, derived from the Trinity Study: if you withdraw no more than 4% of your portfolio per year, historically your portfolio has survived 30+ years without running out. This means your FIRE number is simply your annual expenses divided by 0.04.

How it works

Enter your current age, existing savings, and monthly contribution. Set your expected annual return (7% is the historical US stock market average after inflation) and your annual inflation rate. Finally enter your planned annual expenses in retirement and your chosen safe withdrawal rate.

The calculator uses compound interest formulas to project your portfolio growth month by month until it reaches your FIRE number. The chart shows your portfolio value versus your FIRE target — the moment the green line crosses the orange dashed line is your retirement date.

The real return formula adjusts for inflation: Real Return = ((1 + nominal) / (1 + inflation)) - 1. This gives you purchasing-power-adjusted projections rather than nominal values that look bigger but buy less.

True Time to Retirement

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