coastfire.info
Coast FIRE Calculator

When can you stop saving for retirement?

Find your Coast FIRE number — the portfolio size that grows into your retirement target on its own. Adjust your inputs, share the URL, and see exactly when compound growth takes over.

In today's dollars
0.0% 7.0%20.0%
Long-term nominal return on a diversified portfolio (S&P 500 ≈ 10% historical)
0.0% 3.0%10.0%
Long-term US average ≈ 3%
2.0% 4.0%7.0%
Trinity-study guideline ≈ 4%
0.00% 0.10%2.00%
Weighted expense ratio of your portfolio (broad index funds ≈ 0.05–0.10%)
Real return3.8%

Net worth projection

Inflation-adjusted, in today's dollars

You're 32 years from Coast FIRE.
At your current pace, you'll hit your Coast FIRE number at age 62. You can stop contributing then and still reach your FIRE number by retirement.

Projection based on coasting at the Coast FIRE milestone.

Coast FIRE number
$272,322

at your current age

FIRE number
$1,000,000

in today's dollars

Projected net worth
$1,007,036

at retirement

Retirement income
$40,281

annual, today's dollars

What is Coast FIRE?

Coast FIRE is the moment your investments are large enough to grow into your full retirement target — your FIRE number — without any further contributions. From that point on, you can coast: keep working to cover today's expenses, but no longer save for retirement. Compound growth handles the rest.

It's a milestone within the broader FIRE movement (Financial Independence, Retire Early). Reaching Coast FIRE doesn't mean you stop earning. It means saving becomes optional, freeing you to take a lower-paying job, switch careers, take a sabbatical, or simply spend your full paycheck without sliding backward.

How the math works

Three numbers do all the work:

  • FIRE number — the portfolio size that funds your retirement spending forever, computed as annual spending ÷ safe withdrawal rate. At a 4% withdrawal rate, $40,000 of annual spending requires $1,000,000.
  • Real return — your investment return after inflation and fees. A 7% nominal return with 3% inflation and 0.1% fees yields a real return near 3.8%.
  • Coast FIRE number at any age — the FIRE number discounted backward by your real return. Reach this and growth alone gets you to retirement.

Methodology

Every figure in the calculator is reported in today's dollars, so the numbers stay meaningful regardless of how far away retirement is. Here's exactly what happens behind the scenes.

Real return

real_return = (1 + growth − fees) ÷ (1 + inflation) − 1

Subtracting fees from your nominal growth rate and then dividing through by inflation produces the inflation-adjusted return. This is the rate used for every projection in the chart.

FIRE number

fire_number = annual_spending ÷ safe_withdrawal_rate

The classic 4% rule, drawn from the Trinity Study, suggests a portfolio can sustain a 4% withdrawal rate adjusted for inflation across most historical 30-year retirements.

Coast FIRE number

coast_fire_number(age) = fire_number ÷ (1 + real_return)retirement_age − age

The FIRE number discounted by real return for the years remaining until retirement. The further out retirement is, the smaller the Coast FIRE target — compound growth has more time to work.

Projection

The chart simulates each year from your current age to retirement. Within a year, contributions are applied monthly and balances compound at (1 + real_return)1/12 − 1. Two scenarios run in parallel:

  • With continued contributions — you keep saving at your monthly rate through retirement.
  • Coasting — you stop contributing the year you cross the Coast FIRE target line. From then on, balance grows on its own.

Caveats

This is a planning tool, not a guarantee. Returns vary, inflation surprises, careers change. Use the calculator to explore scenarios, not to plan your life around a single number.

Frequently asked questions