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Results are hypothetical illustrations based on the numbers you enter and simple assumptions: a constant return, with no taxes, fees or inflation unless stated. They are not predictions or guarantees; real returns vary from year to year and can be negative, and investing can lose money. Educational content only. Not financial advice. See our Disclaimer.
Quick answer: Your Coast FIRE number is your retirement target (yearly spending × 25, the 4% rule) divided by (1 + real return) to the power of the years left until retirement. Spending $50,000 a year means a $1.25M target; at a 7% real return that needs about $117,000 invested at 30, $230,000 at 40 or $453,000 at 50 (retiring at 65). Hypothetical, not guaranteed.
Also written CoastFIRE or Coast FI: this calculator finds the amount that, left alone, grows into your retirement number by itself.
What is Coast FIRE?
Coast FIRE is the point where your investments, left alone, will grow into a full retirement fund by the time you retire — so you can stop saving for retirement and only need to cover today’s bills. You still work; you just stop sprinting.
The two numbers
FIRE number = yearly spending ÷ 4% (so $50,000 a year needs $1.25M). Coast number = that FIRE number discounted back to your age at your expected real return. At 7% real, $1.25M at 65 is only about $117,000 at age 30.
Why use a real return?
A 7% real (after-inflation) return keeps everything in today’s dollars, so the spending number you type stays meaningful. Nominal returns around 10% minus roughly 3% inflation land in the same place.
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Open calculator →Questions people ask
What is a Coast FIRE number?
The amount you need invested today so that, with no further contributions, growth alone reaches your retirement number by your retirement age. It is your FIRE number divided by (1 + real return) to the power of years remaining.
Is the 4% rule safe?
It comes from historical US data (the Trinity study) for 30-year retirements. Many planners use 3.5% for longer horizons; you can change the withdrawal rate in the calculator.
Does Coast FIRE mean I can retire?
No — it means you can stop adding to retirement savings. You still need income for current expenses until you actually retire.
How much do I need to coast FIRE by 30?
It depends on your target. For a $1,000,000 retirement number at 65 and a 7% real return, about $93,700 invested by 30 grows to the full amount with no more contributions. For a $1.25M target, about $117,000.
What is the difference between Coast FIRE and Barista FIRE?
Coast FIRE means your retirement savings can grow to your target on their own, so you only need income to cover today's costs until you retire. Barista FIRE means you already draw on your portfolio and use part-time work to cover the gap. Coast FIRE is the earlier, safer milestone.