Q: How to calculate your Coast FIRE number

It's simple but many online tools get it wrong . Here is the breakdown: The number of years till retirement: 67 − 35 = 32 Annual spending at retirement adjusted for inflation (3.0%): $2,000 × 12 × 1.030^32 = $61,802 How much you need at retirement (SWR 4.0%): $61,802 ÷ 0.040 = $1,545,050 How much you need now (annual growth 10.5%): $1,545,050 ÷ 1.105^32 = $63,292 This is your real Coast FIRE number . It's never more than your full FIRE number — if you could retire outright today, you can certainly coast.

Question 1

What is FIRE?

Accepted Answer

FIRE (Financial Independence, Retire Early) means saving and investing until your money makes enough on its own to cover your living expenses forever. The common target is 25 times your annual spending, based on the idea that you can safely withdraw around 4% a year. Once you reach it, working becomes optional.

Question 2

What is Coast FIRE?

Accepted Answer

Coast FIRE means you've invested enough early on that you no longer need to add to your savings. Compound growth alone will grow your portfolio into a full retirement fund by the time you reach your target age. From that point, you only need to earn enough to pay your current expenses, since your retirement savings are already on track. The effort goes in early, which lets you spend care-free later in life.

Question 3

How to calculate your Coast FIRE number

Accepted Answer

It's simple but many online tools get it wrong. Here is the breakdown:

The number of years till retirement: 67 − 35 = 32
Annual spending at retirement adjusted for inflation (3.0%): $2,000 × 12 × 1.030^32 = $61,802
How much you need at retirement (SWR 4.0%): $61,802 ÷ 0.040 = $1,545,050
How much you need now (annual growth 10.5%): $1,545,050 ÷ 1.105^32 = $63,292

This is your real Coast FIRE number. It's never more than your full FIRE number — if you could retire outright today, you can certainly coast.