Retirement
Coast FIRE Calculator
Coast FIRE is the moment your investments can grow to your full retirement target on their own — so you only need to cover today's expenses, not keep saving. Enter your numbers to see the amount you need invested now and whether you've already reached it.
Formula shown below · Tested against worked examplesHow we verify
Use a real (after-inflation) return — roughly nominal minus 3% — to keep the target in today's dollars.
Your Coast FIRE number: $231,377
Your Coast FIRE number
$231,377
Invested now, this grows to your full FIRE number by retirement with no more saving.
- Full FIRE number
- $1,000,000
- Still to invest
- $81,377
Compare scenariosTry three values of one input
| Annual expenses in retirement | |||
|---|---|---|---|
| Your Coast FIRE number | $208,240 | $231,377+$23,138 | $254,515+$46,275 |
| Full FIRE number | $900,000 | $1,000,000+$100,000 | $1,100,000+$200,000 |
| Still to invest | $58,240 | $81,377+$23,138 | $104,515+$46,275 |
Every other input stays at the value you set above — currently $40,000 for annual expenses in retirement. Differences are measured against the first column.
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How this calculator works
FIRE number = annual expenses ÷ withdrawal rate. Coast number = FIRE number ÷ (1 + real return)^(retirement age − current age). You've 'coasted' once your current savings meet or exceed the coast number.
A single-rate projection in today's dollars. Real returns vary and sequence-of-returns risk is real, so treat Coast FIRE as a milestone to aim for, not a guarantee — and keep an emergency fund and health coverage in mind before easing off work.
Formula
FIRE = Annual expenses ÷ w
Coast = FIRE ÷ (1 + r)ⁿ- w
- Safe withdrawal rate, as a decimal (0.04 for the 4% rule)
- r
- Expected annual REAL return, after inflation
- n
- Years from now until retirement
The coast number is the FIRE target discounted back to today. Reaching it means contributions can stop and compounding alone finishes the job — which is why the horizon does so much of the work here.
What this assumes
- Once the coast number is reached, contributions stop entirely and the balance is left to compound untouched to retirement age.
- A constant real return for the whole coasting period, which may be decades — the assumption does more work here than in almost any other calculator.
- You still cover living costs from income during the coast; this is not early retirement, only the end of retirement saving.
What changes this number
- Years left to compound
- The entire mechanism. Coasting works because time does the remaining work, so it weakens sharply as retirement nears.
- Assumed return
- Small changes compound over decades into large differences. Test it at 5% before relying on 7%.
- Target retirement spending
- Sets the finish line. Lowering it moves the coast number more than any other input.
A worked example
Take the 35, retire at 65, $150k saved scenario. These figures are produced by the calculator above, not written alongside it, so they always match what the tool returns.
What you enter
- Current age
- 35
- Target retirement age
- 65
- Current invested savings
- $150,000
What it returns
- Your Coast FIRE number
- $231,377
- Full FIRE number
- $1,000,000
- Still to invest
- $81,377
Sources
This calculator uses no external data — the result follows entirely from the formula above and the values you enter, so there is nothing to cite beyond the arithmetic.
Calculator last reviewed August 9, 2026. How we verify
Try an example
Frequently asked questions
What is Coast FIRE?
Coast FIRE is having enough invested that, without adding another dollar, compound growth will reach your full retirement number by your target age. Once you 'coast,' you only need to earn enough to cover current expenses — you can stop retirement saving, work less, or take a lower-paying job you enjoy.
How is the Coast FIRE number calculated?
Start with your full FIRE number (annual expenses ÷ safe withdrawal rate, e.g. 25× at 4%). Then discount it back to today using your expected real return over the years until retirement: coast number = FIRE number ÷ (1 + real return)^years. The more years you have, the smaller the amount you need now.
Why use a real return instead of a nominal one?
Because your FIRE number is in today's dollars. Using a real (after-inflation) return — roughly your nominal return minus about 3% — keeps the projection consistent, so you don't overstate how far your current savings will grow in purchasing power.
What's the difference between Coast FIRE and Barista FIRE?
Coast FIRE means your investments will grow to your goal on their own, so you just cover current costs. Barista FIRE is similar but usually implies a part-time job (often for health benefits) to bridge the gap. Both let you ease off full-time work well before traditional FIRE.
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Disclaimer: DayCents provides this calculator for educational purposes only. Results are estimates based on your inputs and the stated assumptions — they are not financial advice, a quote, or an offer of credit. Consult a qualified financial professional before making major money decisions.