Free tool
Coast FIRE Calculator
Coast FIRE is the point where you can stop putting money into retirement and still retire on time. What you already have keeps compounding on its own, so your paycheck only has to cover this year. Put your balances in and see how far off you are.
Retirement and brokerage accounts. Leave out your emergency fund and the home you live in.
7% growth against 3% inflation is 3.9% real. Every figure here is in today's dollars.
Your Coast FIRE number
$427K
Invested by 32, that grows to $1,500,000 by 65 on its own — enough to draw $60,000 a year at 4%.
Invested now
$200,000
Coast FIRE
May 2044 · age 49
Value at 65
$1,869,298
Can live off it
Mar 2055 · age 60
Year by year, to 65
| Age | You'll have | Needed to coast | Difference |
|---|---|---|---|
| 32 | $200,000 | $426,634 | −$226,634 |
| 37 | $339,238 | $516,164 | −$176,926 |
| 42 | $507,695 | $624,483 | −$116,788 |
| 47 | $711,504 | $755,533 | −$44,029 |
| 52 | $958,082 | $914,084 | +$43,998 |
| 57 | $1,256,406 | $1,105,908 | +$150,499 |
| 62 | $1,617,334 | $1,337,986 | +$279,348 |
| 65 | $1,869,298 | $1,500,000 | +$369,298 |
How the math works
Your full FIRE number is what you want to spend each year divided by your withdrawal rate. Spend $60,000, withdraw 4%, and you need $1.5 million. The Coast FIRE number is that figure discounted back to today at whatever your money earns after inflation. Thirty five years at 5% real turns a dollar into $5.52, so the $1.5 million you need at 65 costs you $271,000 at 30.
The dashed line on the chart is that requirement at every age between now and retirement, and it falls as you get older because money invested later has less time to grow. The solid line is what you will actually have. They cross on the day you can stop saving.
What this leaves out
- Social Security. Counting it would lower your number, so leaving it out keeps this on the cautious side.
- Taxes. A dollar in a traditional 401(k) is worth less than a dollar in a Roth. If most of your money is pre-tax, shade the answer down.
- Getting at it early. Retirement accounts charge a penalty before 59½, so retiring before then needs a 72(t) schedule or enough in a taxable account to bridge the gap.
- Sequence of returns. This runs on a smooth average. Real markets arrive in a random order, and a bad first decade hurts far more than a bad last one.
Nothing you type leaves your browser. There is no account, no tracking of your numbers, and nothing saved on a server.
Questions people ask
- How do you calculate your Coast FIRE number?
- Take the yearly spending you want in retirement and divide it by your withdrawal rate, usually 4%, which gives you your full FIRE number. Then discount that back to today at whatever your money earns after inflation. The formula is FIRE number ÷ (1 + real return) ^ years left. Reach that figure and compounding finishes the job for you.
- What is a good Coast FIRE number?
- It depends on what you plan to spend and how many years of compounding you have left, so there is no single figure. A 30 year old who wants $60,000 a year and plans to retire at 65 needs about $285,000 invested at a 5% real return. The same person retiring at 55 needs roughly $465,000. Time does most of the work, so the younger you are the smaller the number.
- How much do you need to Coast FIRE at 30?
- About $285,000, if you want $60,000 a year, retire at 65, withdraw 4% and earn 5% after inflation. Change any one of those and the answer moves a long way, which is why it is worth running your own numbers instead of borrowing someone else's.
- Does this calculator account for inflation?
- Yes. You give it a return and an inflation rate, and it projects on the real return between the two. Everything on the page is in today's money, so $60,000 a year means $60,000 of what it buys right now.
- What is the difference between Coast FIRE and FIRE?
- FIRE means you have enough to stop working and live off the portfolio today. Coast FIRE comes earlier: you have enough that you never need to add another retirement dollar, but you still work to pay for this year. Everything you earn after that point goes on your current life instead of your seventies.
- Can couples use this calculator?
- Yes. Put both partners' accounts in the list and use your joint yearly spending. If there is a big age gap, run it on the older partner's age, since that gives you the shorter compounding window and the safer answer.
I built this for myself first, then cleaned it up to share. I write about building tools like this over on the blog, and there are more of them on my work page. This is an estimate, not financial advice.