savingsmath

Have I saved enough to stop saving for retirement?

Coast FIRE means your pot could grow into your retirement target on its own, with no more deposits, by the time you retire. Type your age, your retirement age, what you have and what you want to spend; the answer is the amount you need today.

Your answer

At 30, about €65,265 invested today could grow to €360,000 by 65 without another deposit.

  • €65,265Coast FIRE numberenough at 30 to coast to the target by 65
  • €15,265Still missingto reach the Coast FIRE number today
  • €360,000Target at 6525 × a year of spending

Grows at 5% a year after inflation; the target is 25 times a year of spending under the 4% rule, a rule of thumb from US market history, not a guarantee. Before fees and tax. An estimate, not a promise.

The full retirement calculator shows the pot year by year, with inflation, tax and the split between index funds and bonds, and how long it then lasts.

Open the retirement calculator with these numbers

Illustration only, not investment advice. Assumes a steady return; real returns vary.

How the Coast FIRE number is worked out

The target is 25 times a year of spending. The Coast FIRE number is that target discounted back to today at the real return: the amount which, growing at 5% a year above inflation for the years until you retire, lands on the target with no further deposits.

The further away retirement is, the smaller the number, because compounding has more years to work. That is why Coast FIRE is mostly a young person's milestone: at 30 with retirement at 65, a pot of a few years of spending is enough; at 55 it is nearly the whole target.

Reaching it does not mean stopping work: you still pay today's bills from today's income. It means retirement is funded if the assumed return holds, which it may not, so most people keep saving something.

Coast FIRE is the point where the money you have already saved could grow, on its own, into what you need for retirement. You keep working to pay today’s bills, but you no longer have to set anything aside for later. Your savings “coast” the rest of the way.

It is compound interest run backwards. Instead of asking “what does this amount grow into?”, Coast FIRE asks “how much do I need today to grow into my target by a certain age?”

Step 1: the FIRE number

Coast FIRE starts from your FIRE number, the pot that could pay for your life in retirement:

FIRE number = yearly spending in retirement ÷ withdrawal rate

With a 4% withdrawal rate, someone who expects to spend 30,000 a year needs 30,000 ÷ 0.04 = 750,000.

Step 2: discount it back to today

Then you ask how much money, invested today and left alone, would grow into that number by your retirement age:

Coast number = FIRE number ÷ (1 + real return) ^ years to retirement

The real return is the yearly return after inflation. With 7% a year before inflation and 2% inflation, the real return is (1.07 ÷ 1.02) − 1, about 4.9%.

Worked examples

Same goal for everyone: 750,000 in today’s money by age 65, assuming a steady 5% a year after inflation.

Age today Years to 65 Coast number
25 40 106,534
35 30 173,533
45 20 282,667

The earlier you start, the smaller the number, because the money has more years to compound. At 25, about a seventh of the goal is enough; at 45, it takes more than a third.

When could you reach it?

The Coast number shrinks every year you get closer to retirement, while your savings grow. Coast FIRE is the first age where the two meet.

Say you are 30 with nothing saved and put away 1,000 a month, growing at the same 5% after inflation. Your balance passes the (shrinking) Coast number at around age 47. From then on, under these assumptions, the pot could reach 750,000 by 65 without another deposit.

With 750 a month, the same crossing happens at about 58. With 500 a month, it never happens before 65: at that rate, you would still be saving at retirement.

To check the formula by hand: a FIRE number of 1,500,000, a 7% real return and 35 years to go give a Coast number of 1,500,000 ÷ 1.07^35 ≈ 140,494.

What the number assumes

Coast FIRE turns a long, uncertain future into one tidy figure, so it is worth knowing what is folded into it:

  • A steady return every year. Real markets go up and down. A few bad years after you stop saving could leave you short, and you might need to save again for a while.
  • Your spending stays as planned. If retirement costs more than you expect, the FIRE number rises and so does the Coast number.
  • The withdrawal rate holds. The 4% rule is a rule of thumb from past US data for 30-year retirements, not a promise. A lower withdrawal rate makes the FIRE number, and the Coast number, larger.
  • No fees or tax. Fund fees lower the return every year, and tax can apply when you sell. Both make the real growth rate smaller.
  • Nothing is taken out early. The money only coasts if you leave it alone.

That is why many people treat Coast FIRE as a milestone to check now and then, not as a finish line.

Coast FIRE and the other kinds of FIRE

  • Full FIRE: the pot already covers your spending; work becomes optional.
  • Barista FIRE: part-time work covers part of your costs while the pot covers the rest.
  • Coast FIRE: work covers all of today’s costs; the pot only has to be left to grow.

Try it yourself

A dedicated Coast FIRE calculator is on its way. Until then, the compound interest calculator shows what a single amount could grow into: enter your savings as the starting amount, set the monthly saving to 0, and switch on inflation to see the result in today’s money. The formulas behind every number are in our methodology.

Educational content, not financial advice. The examples assume a steady return; real returns vary and past returns do not promise future ones.

Questions and answers

What is Coast FIRE?

Having saved enough early that, without adding more, the pot could grow into your FIRE number by a normal retirement age. You still work to pay today's costs, but you no longer need to save for retirement. The example of a gift invested at birth shows the same effect: one amount left alone to grow for decades.

How do I calculate my Coast FIRE number?

Divide your FIRE number by how much money grows until retirement: Coast FIRE number = FIRE number ÷ (1 + real return)^years. With a FIRE number of 360,000, 30 years to go and a return of 5% a year after inflation, that is about 83,300. To check it, enter that amount as the starting sum in the compound interest calculator, set the monthly saving to 0 and switch on inflation. The result depends heavily on the return you assume.

What can go wrong with Coast FIRE?

The number assumes a steady return after inflation for decades. Real markets go up and down, so a weak decade can leave the pot short. It also assumes nothing is taken out early and that your retirement spending matches the plan. That is why many people check it now and then as a milestone rather than relying on it. It is an illustration, not advice.