Coast FIRE Calculator

Q: What return should I use?

There is no single right answer. Long-run U.S. equity averages are commonly cited around 6-10% nominal (historical ranges vary by source and period). Testing a conservative range (5-7%) is the standard, honest approach.

Find the amount you need today so compounding can reach your retirement target on its own.

To reach $1,500,000 by age 65 with a 7% return starting at 30, you would need about $140,494 today — with no further contributions. That is your Coast FIRE number: the lump sum that lets compounding do the rest. Adjust the target, ages or return to model your own path.

Your plan

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Current age

Target retirement age

The age by which you want the target reached.

Target nest egg at retirement

The portfolio you want at your target age.

Expected annual return

Presets are illustrative. Edit the rate to match your own assumption.

Coast FIRE number — what you need today

0 years of runway

Target at retirement–

Compounding runway–

Expected annual return–

PortfolioRetirement target

Show yearly breakdown

Year	Portfolio	Retirement target

How this calculation works

The Coast FIRE number

Your Coast FIRE number is the present value of your retirement target, discounted at your assumed return:

Coast FIRE number = target ÷ (1 + annual return)^years

For a $1,500,000 target at 65 with 35 years of runway at 7%, that is $1,500,000 ÷ 1.07³⁵ ≈ $140,494.

How the target varies with your age

Current age	Years to 65	Coast FIRE number
30	35	~$140,494
40	25	~$276,374
50	15	~$543,669

All rows assume a $1,500,000 target and 7% annual return. The earlier you start, the less you need — that is the pure math of compounding.

Return sensitivity (30 years of runway)

Assumed return	Coast FIRE number
5%	~$347,066
6%	~$261,165
7%	~$197,051
8%	~$149,066

Assumptions

No further contributions are made after today.
Returns compound annually at a constant rate; real markets fluctuate.
No inflation adjustment, taxes or fees are included in the base number.
Reaching a Coast number is encouraging, not a guarantee of retirement readiness.
Results are hypothetical and for education only — not financial advice.

View the formula →

Educational purposes only. Not financial advice. See the full methodology and disclaimer.

Coast FIRE, explained

What is Coast FIRE?

Coast FIRE is the stage where your current savings, compounding at a long-term average return, will reach your retirement target without any further contributions. After this point, work is optional rather than required.

How is the Coast FIRE number calculated?

Divide your target retirement portfolio by (1 + assumed annual return) raised to the number of years until retirement. Example: $1,500,000 ÷ (1.07)^35 ≈ $140,494.

How is Coast FIRE different from regular FIRE?

Regular FIRE requires your whole portfolio to support spending at retirement. Coast FIRE only requires enough today to grow to that portfolio — contributions after "coast" are optional extras.

What return should I use?

There's no single right answer. Long-run U.S. equity averages are commonly cited around 6–10% nominal (historical ranges vary by source and period). Using a conservative range (5–7%) and testing sensitivity is the standard, honest approach.

Does this include inflation?

No. The base number uses a nominal return and a nominal target. Inflation erodes purchasing power over decades, so treat the result as a nominal planning figure — consider a 3% inflation assumption for a purchasing-power view.