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Coast FIRE

How Much Do You Need to Stop Saving for Retirement?

Find your Coast FIRE number the honest way — grown at the real, inflation-adjusted return so a target in today's dollars stays in today's dollars. Powered by live CPI data.

Inflation-adjustedReal vs naive figureLive CPI data

Most coast calculators ignore inflation and under-state your number. This one doesn't — it grows your savings at the real return.

25×

Annual expenses = the standard FIRE target (the 4% safe-withdrawal rule)

$331k

How much the naive nominal method under-states the default coast number by ignoring inflation

~3.7%

Real return on a 7% nominal portfolio after live ~3.2% CPI — the rate that actually matters

Understanding Coast FIRE

What 'coasting' means

Once you hit Coast FIRE, you no longer need to direct every spare dollar into retirement savings. You can take a lower-paying job you love, reduce hours, or simply stop the monthly investing grind — your future is already funded.

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Real growth does the heavy lifting

Because your target is in today's dollars, what matters is the real (after-inflation) return. At a 7% nominal rate and ~3.2% inflation, $100,000 grows to about $247,000 of real buying power over 25 years — coasting works, but the inflation-honest math is what keeps the plan trustworthy.

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Compare to your current savings

Use this calculator alongside your current portfolio value to see how close you are. If you have $80K saved and your Coast FIRE number is $120K, you might be just 2–3 years of focused saving away from financial breathing room.

How the Coast FIRE Calculator Works

Formula

Coast number = Target ÷ (1 + real return)^years, where real return = (1 + nominal) ÷ (1 + inflation) − 1
1

Enter your inputs

Current savings, FIRE target (typically 25× annual expenses), expected nominal return, and years until retirement.

2

Convert to a real return

We remove the live CPI inflation rate from your nominal return using the Fisher equation.

3

Discount the target

We discount your today's-dollars target back at the real return to find the lump sum you need invested now — your Coast FIRE number.

4

Project your savings

We grow your current savings forward at the same real rate to show the gap or surplus versus the number.

Coast FIRE is the moment your invested savings are large enough that, with no further contributions, compound growth alone carries you to a full retirement. The catch most calculators miss: your target is in today's dollars, so the growth that counts is the real (after-inflation) return — not the headline nominal rate.

Using the defaults — $100,000 saved, a $1.5M target, a 7% nominal return and 25 years — the naive nominal method reports a coast number of about $277,000. But after removing live ~3.2% CPI inflation, the real return is ~3.7% and the honest coast number is about $607,000. That $331,000 gap is exactly what under-states so many coast plans, and it's why your current $100,000 (which grows to ~$247,000 of real buying power) still leaves a shortfall to close.

Frequently Asked Questions