Free calculator

Coast FIRE Calculator: When to Stop Saving

Coasting, in FIRE (financial independence, retire early), means the money you have invested could reach your retirement number on its own. See when you would get there.

Nothing you type is saved or sent anywhere, and there is nothing to sign up for.

years

What you already hold in investment and retirement accounts.

0 shows what the money you have does on its own.

Your FI number is built from this: the money that would let work become optional (FI is financial independence).

An assumption, not a forecast. 7% is the app’s default when you have not set your own.

%

65 is the app’s default.

years

Your answer

2 years 10 months

until the coast point, at about age 32. From then, what you have invested would grow to your FI number by 65 with nothing more added.

Your FI number

25 × a year of spending: 2,500 × 12 × 25

750,000

What you have today, left alone, by 65

50,000 growing 7% a year for 35 years

575,308

From your numbers: age 30, adding 500 a month, retiring at 65.

Wealth Mutant is a personal finance app that runs this same Coast FIRE test on your own investment and retirement accounts. Future Self shows where your current pace leads.

See pricing

How the sum works

Your FI number (FI is financial independence, the point where work becomes optional) is 25 times a year of your spending. That is the 4% rule: take 4% of a pot that size each year, and you have one year of your spending.

The coast point is the month when what you have invested, growing at your assumed return with nothing more added, would reach your FI number by your retirement age. The calculator steps forward a month at a time. It adds that month’s growth and what you put in, then checks again.

Growth is worked out monthly: a 7% yearly return becomes 7 ÷ 12, about 0.58%, each month. A calculator that adds growth once a year will give a slightly different date.

The return is yours to choose. Real returns rise and fall from year to year, so try a lower figure to see a more careful answer.

An example

Say you are 30, with 50,000 invested. You add 500 a month, spend 2,500 a month, assume 7% a year and plan to retire at 65. Your FI number is 2,500 × 12 × 25 = 750,000.

Left alone, the 50,000 grows to about 575,000 by 65, short of 750,000, so you are not at the coast point yet. Adding 500 a month, you reach it in 34 months (2 years 10 months), when about 79,700 invested would grow to 750,000 by 65 with nothing more added. With nothing added at all, you never reach it.

Coast, Lean and Fat FIRE

Coast FIRE is a milestone on the way. From there you still earn what you spend, but you no longer need to save for retirement.

Lean FIRE and Fat FIRE are finish lines: work becomes optional on a small yearly budget, or on a comfortable one. Both use the same sum, 25 times the yearly spending you plan for. To try either here, change what you spend each month.

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