Coast FIRE is the moment your investments are large enough that compound growth alone will carry you to financial independence — even if you never save another dollar. You still work to cover today's expenses, but retirement is already handled.
Coast FIRE is a milestone on the path to financial independence. It's the point where your existing investments, through the power of compound growth, will reach your full FIRE number by the time you hit traditional retirement age — without adding a single dollar more.
Once you reach Coast FIRE, the pressure to save aggressively disappears. You still need to earn enough to cover your current living expenses, but every dollar you earn can go toward living your life today rather than funding a distant future.
Think of it this way: regular FIRE means you can quit working entirely. Coast FIRE means you can quit saving entirely. You keep working, but you're free to take a lower-paying job you love, go part-time, freelance, or pursue passion projects — because compound interest is doing the heavy lifting in the background.
The Coast FIRE number tells you how much you need invested today so that compound growth alone reaches your FIRE target by retirement age:
Where r is your expected annual real return (after inflation) and n is the number of years until your target retirement age.
Say you spend $5,000/month ($60,000/year). Your FIRE number is $60,000 × 25 = $1,500,000. You're 30 years old and targeting retirement at 60, so n = 30 years. Assuming a 7% real return:
If you have $197,000 invested at age 30, you've already hit Coast FIRE. Compound growth at 7% will turn that into $1.5M by age 60 — no additional savings needed.
Coast FIRE numbers for a $1.5M FIRE target at 7% real return, retiring at 60
Coast FIRE is not an alternative to FIRE — it's an earlier checkpoint that unlocks major lifestyle flexibility years or even decades before full financial independence. Many people reach Coast FIRE in their late 20s or early 30s while full FIRE may take until their 40s or 50s.
Reaching Coast FIRE changes the game, even if you're years away from full FIRE:
Most Coast FIRE calculators use a single number and a single growth rate. Real life is more complex. NetWorthCast gives you a complete picture:
Coast FIRE is the point where your existing investments will grow to your full FIRE number by retirement age through compound growth alone — even if you never save another dollar. You still work to cover current living expenses, but retirement funding is complete.
Coast FIRE Number = FIRE Number ÷ (1 + expected annual return)^years until retirement. For example, with a $1.5M FIRE target, 7% real returns, and 25 years to go, your Coast FIRE number is $1,500,000 ÷ (1.07)^25 = approximately $276,000.
Regular FIRE means your investments cover all expenses and you never need to work again. Coast FIRE means compound growth will get you there eventually, but you still need to earn income for current expenses. Coast FIRE is reached much sooner and is a milestone on the way to full FIRE.
Not fully. Coast FIRE means you can stop saving for retirement, but you still need income for day-to-day expenses. The upside: you need far less income, so you can switch to part-time work, freelancing, or a lower-paying job you love.
Most calculations use a 7% real (inflation-adjusted) return, based on the long-term average of a diversified stock portfolio. More conservative planners use 5-6%. NetWorthCast lets you set individual return rates per asset for a more accurate projection.
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