Free Coast FIRE CalculatorYour Number in 30 Seconds

Get your Coast FIRE number in seconds—then see whether retirement savings can grow on their own from here.

What's Your Coast FIRE Number?

Your Coast FIRE Number

$329,443

Not reachable by retirement at this contribution

You've covered 15% of the target. Gap: $279,443.

About $1,207 per month would be needed to fund the full retirement target by retirement.

Projected investments at retirement
$189,714
Full retirement nest egg
$1,250,000

Age 30 to 65 · $0/month · 7% nominal return · 3% inflation · 3.88% real return · 4% withdrawal rate

Planning estimate only. This result does not model taxes, investment fees, uneven market returns, account withdrawal rules or life expectancy.

Defaults: retire at 65, $0 monthly contribution, 7% nominal return, 3% inflation, 4% withdrawal

Your Coast FIRE Projection
Behind
No crossing before retirement at age 65
Projected investments: $189,714. Coast target: $1,250,000. Shortfall: $1,060,286.
No new contributions
Projected net worth
Coast FIRE target (rises as retirement approaches)

What does Coast FIRE actually mean?

In one sentence: You've saved enough that compound growth alone can fund retirement—even if you never invest another dollar.

Why it matters: it marks the point where retirement savings may coast, while you only need income for today's bills.

If you skip this checkpoint, it's easy to keep grinding for a full FIRE number you may not need yet—or to cut retirement contributions before the math actually works.

Doing it right helps you:

  • See a clear Coast FIRE number instead of guessing
  • Know when a lower-stress job that covers expenses becomes realistic
  • Pressure-test the answer before you change your savings plan

How does it play out?

  • Save aggressively early in your career
  • Hit your Coast FIRE number
  • Switch to a lower-stress job that just covers your expenses
  • Let your investments grow untouched until retirement

It's the halfway point to full FIRE—for people who don't want to wait until 65 to stop grinding.

Learn more about Coast FIRE →

How do you use this calculator?

1

What's your current age?

Enter how old you are now. Younger ages need a smaller Coast number for the same retirement target, because compound growth has more years to work.

2

When do you want to retire, and on what budget?

Set retirement age and annual retirement spending. Earlier retirement or higher spending raises the Coast FIRE number.

3

What have you already invested?

Enter current invested savings you expect to leave compounding. Under Adjust your plan, you can change nominal return (default 7%), inflation (3%), and withdrawal rate.

4

What do the results mean?

Your Coast FIRE number appears instantly. Orange is projected investments; blue is the Coast target. A crossing marks the first projected Coast age—check assumptions before changing contributions or work.

How is the Coast FIRE number calculated?

Three linked amounts: growth after inflation, the full nest egg at retirement, and the smaller amount today that could grow into that nest egg.

What's the real return?

Nominal return is growth before inflation. Real return is what's left after inflation eats into it.

Real Return = (1 + Nominal Return) ÷ (1 + Inflation) - 1

With a 7% nominal return and 3% inflation, the real return is about 3.88%.

The calculator does not treat 7% as a real return—that 7% is the editable nominal default.

How big is the retirement nest egg?

This is the full amount you want invested by the retirement date—not today's Coast number.

Nest Egg = Annual Expenses ÷ Withdrawal Rate

Example: $50,000/year ÷ 4% = $1,250,000 needed at retirement

The nest egg is the retirement-date target. Today's Coast FIRE number is smaller.

How do you get today's Coast number?

Discount the nest egg back to today using real return and years left until retirement.

Coast Number = Nest Egg ÷ (1 + Real Return)^Years

Where:

  • Real Return = (1 + Return Rate) ÷ (1 + Inflation) - 1
  • Years = Retirement Age - Current Age

Example: Age 35, retire at 65, 7% return, 3% inflation

Real Return = (1.07 ÷ 1.03) - 1 = 3.88%

Coast Number = $1,250,000 ÷ (1.0388)^30 = $398,578

At age 35, $398,578 is the amount that would grow to the $1,250,000 retirement target if the selected assumptions hold and the money remains invested.

Sources and research basis

Withdrawal-rate research behind the editable 4% assumptionAAII: Retirement Savings, Choosing a Withdrawal Rate That Is Sustainable

AAII hosts the Cooley, Hubbard and Walz research. Historical withdrawal results do not guarantee a future outcome.

Why past returns cannot promise future resultsSEC Investor.gov: Past Performance

The SEC states that past performance does not necessarily predict future results. The 7% nominal return is an editable assumption.

US inflation definition and official data: US Bureau of Labor Statistics: Consumer Price Index

BLS publishes the Consumer Price Index. The calculator uses your inflation input rather than predicting future inflation.

Sources last reviewed: July 25, 2026

What counts as current savings?

Count money already invested that you expect to leave compounding for retirement.

Usually include

  • Retirement accounts such as a 401(k), 403(b), traditional IRA or Roth IRA
  • Taxable brokerage investments set aside for retirement

Usually keep separate

  • Emergency cash and money reserved for near-term spending
  • Your primary home unless your plan converts home equity into retirement assets
  • Future income, employer matches not yet received, pensions and Social Security

This calculator does not adjust for taxes by account type. Use the amount available to your plan, and get tax advice when account treatment could change the decision.

How do you stress-test the result?

One estimate cannot show how sensitive the answer is. Run it again with:

  • A lower nominal return
  • Higher inflation
  • A lower withdrawal rate
  • Then compare the Coast number, required monthly contribution and retirement shortfall with your first run

This is a sensitivity check—not a forecast or a best/worst-case range.

What does this calculator leave out?

This is an educational estimate, not financial, tax or investment advice. It uses the return, inflation, withdrawal and contribution assumptions you enter. It does not model:

  • Taxes on contributions, growth or withdrawals
  • Investment fees or changes in asset allocation
  • Sequence-of-returns risk from uneven annual market results
  • Withdrawal rules, penalties or required distributions for specific accounts
  • Life expectancy, healthcare shocks or changes in retirement spending
  • Market guarantees or the probability that a plan succeeds

Talk with a qualified financial professional before reducing retirement contributions or changing your work plan.

Sources last reviewed: July 25, 2026

Common Coast FIRE questions

The calculator starts with a 7% nominal return and 3% inflation—about a 3.88% real return: (1.07 ÷ 1.03) - 1.

Past returns do not predict future results. Review the inputs, then stress-test a less favorable set.

Have more questions? Drop us a line.

"It's not that I don't want to work hard—I just want to work hard for myself."

May you reach the shore soon 🌅