FIRE & Retirement calculator

Coast FIRE Calculator

Find out if your current savings will coast to a full retirement with no further contributions — and your exact Coast FIRE number.

In today's dollars
After inflation
4% = 25x spend

What Coast FIRE means and how to reach it

Coast FIRE — short for "coast to financial independence" — is the point at which you have already invested enough that compound growth alone, with no further retirement contributions, will reach your full retirement target by the time you retire. Once you hit it, you still need to earn enough to cover your current living expenses, but you no longer have to save for retirement. That frees people to downshift to part-time or lower-paying work, change careers, or take a break while their existing investments keep compounding.

The math is the compound-interest formula run in reverse. Your retirement target is usually your expected annual spending times 25 (the 4% rule). Your Coast FIRE number is that target discounted back to today at your expected real return: Coast FIRE number = target ÷ (1 + r)n, where r is your inflation-adjusted return and n is the years until retirement. Because n is an exponent, time is the most powerful lever — a 30-year-old needs far less invested today than a 45-year-old to coast to the same goal. This calculator computes your number and compares it against your current balance to give a clear verdict.

It helps to place Coast FIRE among the other FIRE milestones. Full FIRE means you have the entire 25× nest egg and can stop working altogether. Lean and Fat FIRE describe smaller or more generous spending targets. Coast FIRE is the halfway marker: the savings are done, but you still work to pay the bills. Note that it is a moving target — your number falls each year as retirement nears, and it shifts with your spending estimate and assumed return, so it is worth revisiting periodically. Use real returns so the result is in today’s dollars.

Frequently asked questions

What is Coast FIRE?
Coast FIRE is the point at which you have already invested enough that compound growth alone — with no further retirement contributions — will grow your portfolio to your full retirement target by your retirement age. Once you reach it, you still need to cover your current living expenses, but you no longer have to save for retirement. This gives people the freedom to scale back to lower-paying or part-time work, change careers, or take time off while their existing investments keep compounding toward the goal.
How is the Coast FIRE number calculated?
The Coast FIRE number is the present value of your future retirement target, found by discounting that target back to today at your expected real (inflation-adjusted) return: Coast FIRE number = retirement target ÷ (1 + real return)^(years until retirement). The retirement target itself is usually your annual spending times 25 (the 4% rule). Because the years-to-retirement term is an exponent, more time to compound dramatically lowers the amount you need today — which is why reaching Coast FIRE young is so powerful. See the methodology page for full detail.