Coast Fire Calculator

Display currencyFormatting only. This does not change the calculation.

How is your retirement spending stated?

Retirement spending, in today’s money (USD)What you expect to spend each year (or month) once you stop working, in today’s prices.

Safe withdrawal rate (%)4% is the Bengen/Trinity figure for a 30-year horizon. Retiring earlier, or wanting more certainty, argues for a lower rate.

Your age now

Age you want to retire

Invested assets you already have (USD)Money that is actually invested and left alone - not cash you plan to spend.

Amount you invest each year from here (USD)Coast FIRE asks what happens with zero, so this is only used for the "when do I get there" answers.

Expected nominal annual return (%)Before inflation. Your own assumption; nothing here forecasts a market.

Expected inflation (%)Subtracted from the return so that the answer stays in today’s money.

Coast FIRE number today

395,331.94

FIRE and Coast FIRE Calculator

FIRE number

1,500,000.00

Annual spending used

60,000.00

Real return after inflation

3.88 %

Years until retirement

35.00

Still needed to reach Coast FIRE

295,331.94

Amount past Coast FIRE

0.00

Coast FIRE reached?

Not yet - 295331.94 short of the amount that would coast to the target.

What today’s portfolio alone becomes by retirement

379,427.98

Years until full FIRE

39.02

Age at full FIRE

69.02

Worked out from Bengen WP, Determining Withdrawal Rates Using Historical Data, Journal of Financial Planning, October 1994 - the origin of the 4% initial withdrawal rate and 2 other sources.

On these assumptions the portfolio never catches the Coast FIRE target before the retirement age chosen.

A safe withdrawal rate is a historical observation, not a guarantee. This projection uses one constant real return and one constant spend; real sequences of returns, taxes, healthcare and a changing life do not behave that way.

How this is worked out

5 steps

FIRE number = annual spending / safe withdrawal rate = 60000 / 0.04 = 1500000 (that is 25 times spending).
Real return = (1 + 0.07) / (1 + 0.03) - 1 = 0.03883495, so the FIRE number stays in today's money.
Growth factor over 35 years = (1 + 0.03883495)^35 = 3.7942798.
Coast FIRE number = FIRE number / that factor = 1500000 / 3.7942798 = 395331.94.
Your 100000 left completely alone becomes 379427.98 by age 65.

Coast target by agetable

age	coastTarget	projectedIfStoppedNow	projectedWithContributions
30	395,331.94	100,000	100,000
35	478,293.71	120,985.34	185,830.06
40	578,665.29	146,374.54	289,671.85
45	700,100.2	177,091.74	415,305.2
50	847,018.63	214,255.05	567,303.14
55	1,024,768.41	259,217.21	751,198.37
60	1,239,819.59	313,614.83	973,684.65
65	1,500,000	379,427.98	1,242,860.44

Results are general information, not financial, tax, legal, medical or engineering advice.