Free calculator · Coast FIRE
Coast FIRE Calculator
Coast FIRE is the point where the money you've already invested will grow to your full FIRE number by your retirement age without you adding anything more, so from then on you only need to earn enough to cover your current spending.
To retire at 60 spending €40,000 a year, you need €1,000,000 at a 4% withdrawal rate. At a 5% real return, €231,377 invested today grows to that by itself. You have €100,000. Saving €20,000 a year, you reach Coast FIRE in 8 years, around age 38. From then on, growth alone can take you to €1,000,000 by 60.
- Runs in your browser
- Nothing sent or saved
How to calculate your Coast FIRE number
Start from your FIRE number, then work out how much you'd need invested today for growth alone to get there by your retirement age:
Coast FIRE number = FIRE number ÷ (1 + real return)^years to retirementFIRE number = yearly spending in retirement ÷ withdrawal rate
Once your investments reach your Coast FIRE number, you can stop adding to them: compound growth does the rest. Each year you wait, there is less time left to grow, so the Coast FIRE number rises towards your full FIRE number.
The time to Coast FIRE starts from what you have invested now, adds what you save each month, and grows the total at your real return, compounded monthly, until it reaches the Coast FIRE number for that month.
Worked example
Say you're 30, want to retire at 60 and expect to spend €40,000 a year in today's money.
- At a 4% withdrawal rate, your FIRE number is €40,000 ÷ 0.04 = €1,000,000.
- Over the 30 years to 60, a 5% real return grows money 1.0530 ≈ 4.32 times.
- Your Coast FIRE number is €1,000,000 ÷ 1.0530 = €231,377.
- You have €100,000 invested, 43% of the way there. Saving €20,000 a year, you reach Coast FIRE in 8 years, at 38, with about €343,000 invested. From then on, growth alone takes it to €1,000,000 by 60.
Assumptions
- Everything is in today's money. The return is a real return, after inflation, so your spending and your FIRE number don't need adjusting for inflation.
- The return is the same every year. Real markets rise and fall, and over a coast of 20 or 30 years a small change in the return makes a big difference.
- Once you reach Coast FIRE, you add nothing more to these investments and take nothing out until you retire.
- Tax, fees and pensions aren't modelled. Include tax on withdrawals in your spending, and use a return after fees.
- The default 5% real return is the assumption the Addeo app uses in its briefing. It is not a forecast: try 3% or 4% to see a more cautious plan.
- The 4% rule comes from historical US returns over 30-year retirements. It is a rule of thumb, not a guarantee.
Coast FIRE FAQ
What is Coast FIRE?
Coast FIRE is the point where your investments, left to grow, will reach your full FIRE number by your chosen retirement age without you adding anything more. From then on, you only need to earn enough to pay your current living costs, and your retirement savings coast the rest of the way.
How is the Coast FIRE number calculated?
Work out your FIRE number (yearly spending in retirement divided by your withdrawal rate), then divide it by how much money grows before you retire: (1 + real return) to the power of the years until then. At a 5% real return over 30 years, money grows about 4.32 times, so a €1,000,000 FIRE number needs €231,377 invested today.
What's the difference between Coast FIRE and Barista FIRE?
With Coast FIRE, your portfolio isn't paying for anything yet: you work to cover your costs while your investments grow untouched. With Barista FIRE, you've left full-time work and your portfolio pays part of your spending, while part-time income covers the rest.
Should I use a real or a nominal return?
A real return, after inflation. The calculator works in today's money, and a 5% real return is roughly a 7% to 8% nominal return when inflation runs at 2% to 3%. If you enter a nominal return, your Coast FIRE number will come out too low.
What if markets do worse than I expect?
Then your investments may not reach your FIRE number by your retirement age, and you'd need to save more, work longer or spend less. Coast FIRE leans heavily on the return you assume over many years, so check your plan each year and try a lower return to see how much margin you have.
Does this calculator store or send my numbers?
No. The maths runs in your browser, and the page is built so it can't send data anywhere. It has no analytics and no tracking, and it doesn't save what you type.
Addeo
See where you stand on every FIRE path, privately.
Addeo tracks your net worth and plans Lean, Coast, Barista and Fat FIRE on your phone, encrypted. No bank logins, no account. Coming soon to iPhone and Android.