Most people in the FIRE community talk about one finish line: the day you have enough invested to quit work entirely. But there's an earlier, quieter milestone that changes your life well before that — and a lot of people hit it without realizing it.
It's called Coast FIRE. And reaching it means you can stop saving for retirement entirely, keep working a job that just covers today's bills, and still retire comfortably at a normal age. Your existing investments "coast" the rest of the way on compound growth alone.
For a lot of people, Coast FIRE is more realistic and more immediately useful than full financial independence. You don't need millions. You need enough, early enough, that time does the rest of the work. This guide explains exactly what Coast FIRE is, how to calculate your number, and the traps that make the back-of-the-napkin math lie to you.
What Coast FIRE actually means
Traditional FIRE is about hitting a portfolio large enough to live off forever — usually 25 times your annual spending, based on the 4% rule. Coast FIRE is different. You've hit Coast FIRE when your current investments, left completely alone with no further contributions, will grow to your full retirement number by the time you actually retire.
Here's the key word: alone. After Coast FIRE, you don't add another dollar to retirement accounts. You still work — you just only need to earn enough to cover your current living expenses. Rent, groceries, travel, the dog's vet bills. The retirement part is already handled. It's just sitting in the market compounding.
A quick example. Say you're 32, and your number for a full retirement at 65 is $1.5 million. If you already have around $300,000 invested, and it grows at a conservative 5% a year after inflation, it reaches about $1.5 million in 33 years without you adding a cent. You've hit Coast FIRE. You could downshift to a less stressful job, go part-time, or start a business that pays less — as long as it covers today's expenses, your retirement is on autopilot.
That's the appeal. Coast FIRE buys you options decades before traditional FIRE does.
Coast FIRE vs. Barista FIRE vs. full FIRE
These terms get tangled, so here's the clean version.
Full FIRE is enough invested to cover all your living expenses indefinitely. You never have to work again.
Coast FIRE is enough invested that you never have to save for retirement again, but you still work to cover current expenses. Your nest egg is done growing toward the goal on its own.
Barista FIRE is a close cousin — you've saved enough that a low-stress, often part-time job (the classic example being a barista, partly for the health insurance) covers your remaining expenses, sometimes with small portfolio withdrawals. Coast FIRE is the version where the day job still covers everything and the portfolio is untouched until retirement.
The common thread: all three are about reducing how hard your labor has to work by letting your money work instead.
How to calculate your Coast FIRE number
There are two numbers you need: your full retirement target, and the amount you need invested today to reach it on autopilot.
Step 1: Find your full retirement number
Start with your expected annual spending in retirement. Multiply it by 25 (the inverse of the 4% rule). If you expect to spend $60,000 a year, your full number is $1.5 million.
If you want to be more conservative, multiply by 28 or 30 instead, which corresponds to a more cautious 3.3–3.5% withdrawal rate. Many in the FIRE community have shifted toward these lower rates after research on longer retirement horizons.
Step 2: Discount that number back to today
This is the part the napkin math gets wrong. You need to figure out how much money invested now will grow into your full number by your retirement age. That's a present-value calculation:
Coast FIRE number = Full retirement number ÷ (1 + r)^n
Where r is your expected real (after-inflation) annual return, and n is the number of years until you retire.
Let's run it. You're 35, retiring at 65, so n = 30. Your full number is $1.5 million. Assume a 5% real return (a deliberately conservative figure — more on that below):
$1,500,000 ÷ (1.05)^30 = $1,500,000 ÷ 4.32 = about $347,000
So at 35, if you have roughly $347,000 invested, you've hit Coast FIRE. You can stop contributing and still land at $1.5 million by 65.
Notice how sensitive this is to your assumed return. At 7% real instead of 5%, that same $1.5M target only requires about $197,000 today. That's a $150,000 swing based purely on a two-point return assumption — which is exactly why you should be careful here.
Step 3: Compare to what you actually have
Subtract your current invested balance from your Coast FIRE number. If you're above it, congratulations — you're already coasting. If you're below it, the gap tells you how much more you need before you can ease off the gas.
The assumptions that quietly break the math
Coast FIRE calculators are everywhere, and most of them are too optimistic. Here's where the simple formula misleads.
Your return assumption is doing all the heavy lifting
As the example above showed, the difference between a 5% and 7% real return completely changes your number. The historical real return of the U.S. stock market is often quoted around 7%, but that's an average across a century, including extraordinary runs. Sequence of returns — the order in which good and bad years arrive — matters enormously, and a decade of flat markets early on can leave you well short. Using 5% real instead of 7% builds in a margin of safety. If you hit your number at the conservative rate and the market does better, you simply retire earlier or richer.
Inflation has to be in real terms — everywhere
If you're using a nominal return (say 9–10%), your retirement number also has to be inflated to future dollars. Mixing a real spending target with a nominal return — or vice versa — produces nonsense. The cleanest approach is to do everything in today's dollars using a real return. That way $1.5 million means $1.5 million of today's buying power, and you don't have to guess what a loaf of bread costs in 2056.
Taxes don't disappear at Coast FIRE
A $1.5 million balance is not $1.5 million of spendable money if most of it sits in a traditional 401(k) or IRA. Withdrawals from those accounts are taxed as ordinary income. A dollar in a Roth is worth more than a dollar in a traditional account, which is worth more than a dollar in a taxable brokerage with embedded capital gains. Coast FIRE math that ignores the tax treatment of where your money lives overstates how far you've actually coasted.
"Stop saving" usually still means employer matches and HSAs
In practice, very few people who hit Coast FIRE literally stop all retirement saving — they keep the free money from a 401(k) match and the triple tax advantage of an HSA. That's fine. Coast FIRE is a threshold, not a vow. Crossing it means the pressure is off, not that you have to leave money on the table.
What Coast FIRE looks like in real life
The point of Coast FIRE isn't to quit — it's to choose. Once you've crossed the line, the question stops being "how do I maximize savings" and becomes "what do I actually want my working years to look like?"
Some people drop to four days a week. Some leave a high-paying, high-stress role for something they find meaningful but lower-paid. Some take a sabbatical, or finally start the business they've been sitting on, knowing their retirement is already funded. The math gives you permission to make those moves without torching your future.
It also reframes a stressful question — "am I saving enough?" — into a clear, answerable one: "have I crossed my Coast FIRE line yet, and if not, how far away am I?"
Modeling Coast FIRE without a fragile spreadsheet
The formula above is a useful starting point, but it's a single snapshot with a single return assumption. Real life has variable income, a job change, a home purchase, kids, Social Security, and a tax bill that shifts every year. A one-line present-value calculation can't see any of that.
This is the gap Tally was built to close. Instead of a static formula, it runs a full lifetime forecast — connecting your real accounts, projecting growth year by year, and layering in federal and state taxes, inflation, Social Security, and required minimum distributions. You can model "what if I stop contributing at 40 and just coast?" as a what-if scenario and watch your actual balance curve out to retirement, side by side with your current path. You see not just whether you've hit Coast FIRE, but what crossing that line frees you to do.
If you've been running Coast FIRE numbers on a spreadsheet and second-guessing the assumptions, you can connect your accounts and see a real projection with proper tax modeling in a few minutes. Tally is $7.99/month or $79/year, with a 14-day free trial and no credit card required to start. It's a simple way to find out exactly where your coast line is — and how much closer it might be than you think.