Coast FIRE is the point where your invested balance would grow into your retirement number all by itself — no further contributions needed. Past it, work only has to cover today's bills; compounding handles retirement. It means you can stop saving, not stop working.

How is the coast number calculated?

Your retirement target (annual spending divided by your withdrawal rate, inflated to retirement-year dollars) discounted back to today at your expected return: target × (1+inflation)^years ÷ (1+return)^years. It rises as you age because there's less time left to compound.

Does coasting mean I can quit my job?

No — that's the most common misreading. Coasting means your retirement is funded by growth alone, but your job still has to cover your living costs until retirement age. Quitting entirely requires the full FIRE number, not the coast number.

What withdrawal rate should I use?

The classic guideline is 4% (your target = 25× annual spending), based on historical 30-year retirements. Earlier retirees often prefer 3.25–3.5% for longer horizons. It's a planning guideline, not a guarantee — a lower rate builds in more cushion.

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Coast FIRE Calculator

Find your coast number — the balance that grows into your retirement target all by itself — and the age you'll reach it at your current savings pace. Everything runs in your browser; nothing is sent anywhere.

Current age

Retirement age

Retirement spending / yr

Withdrawal rate

Invested balance today

Saving per month

Expected return (before inflation)

Inflation

Your coast number today

You have

Coast age at your pace

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Retirement target (today's $)

Want to coast by a certain age?

age

Your balance vs. the coast line

Your balance (with saving) Coast requirement

Worth knowing: coasting means you can stop saving, not stop working — your job still covers spending until retirement. And the path assumes a steady return; a bad decade can move your coast age materially. Balances shown in today's dollars.

What Coast FIRE actually is

Coast FIRE is the least extreme member of the FIRE (Financial Independence, Retire Early) family, and arguably the most practical. The idea: at some point, the money you've already invested will grow into your full retirement number without another dollar of contributions — compounding does the rest of the work. Once your balance crosses that line, retirement is funded. Working is still necessary, but only to pay for today; every optional dollar becomes truly optional.

That changes decisions long before retirement. Past your coast number, you can take the lower-paying job you'd enjoy more, work fewer hours, absorb a career break — without touching the retirement math.

How the coast number is computed

Three steps. First, your retirement target in today's dollars: annual spending ÷ withdrawal rate (at 4%, that's 25× spending). Second, inflate it to retirement-year dollars, because prices won't stand still. Third, discount that back to today at your expected return — the result is the balance that, left alone, compounds into the target right on schedule.

Show me the formula

Coast number today = (spending ÷ SWR) × (1 + inflation)ⁿ ÷ (1 + return)ⁿ

where n is years until retirement. Notice the tug-of-war: inflation grows the target while your return shrinks the requirement — the gap between the two rates is what makes coasting possible at all. The coast requirement rises every year you age, because there's less time left to compound.

The coast age — the number this page adds

Most coast calculators stop at "here's your number." The more useful question is when you'll cross it: keep saving at your current pace and your balance rises while the coast line rises to meet you — where they intersect is your coast age. From that year to retirement, saving is a choice, not a requirement. Try moving the monthly savings input and watch the crossing slide.

Common questions

Can I quit my job once I hit my coast number?

No — that's the classic misreading. Coasting funds retirement, not the years between now and then. Your job (or some income) still has to cover living costs until retirement age. Quitting outright needs the full FIRE number: the retirement target itself, reachable today.

What return should I assume?

This calculator asks for a nominal return and handles inflation separately, so use a nominal figure — many people model diversified stocks at 6–8%. An optimistic return shrinks the coast number, which makes progress look better than it is. Try 6% and 8% and look at the spread.

Is the 4% rule safe for early retirees?

The 4% guideline was built on 30-year retirements. The historical backtests behind the 4% rule fail more often over longer horizons, which is why early retirees often use 3.25–3.5% — that raises the target (and your coast number) but adds real cushion. Lower the withdrawal rate input to see the effect.

What about taxes and account access?

Not modeled here. Withdrawals from pre-tax accounts get taxed, and most retirement accounts lock until 59½ — both matter for the full plan. A complete model needs your real accounts, which is what the Tesserae Plan does.

The coast number is a sketch — the plan is the answer

Tesserae computes this same milestone against your real accounts — with taxes on withdrawals, Social Security, account access ages, and 1,000-run market odds — and tells you honestly whether the whole plan holds. Privacy-first: you enter your own numbers, and we never touch your bank login.

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