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Calculator Answers

Coast FIRE Calculator

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A Coast FIRE calculator is a financial planning utility that calculates the target savings balance needed to retire comfortably at a chosen age without adding further retirement contributions. Coast FIRE is achieved when current savings, compounded over the remaining years to retirement without new deposits, grow to satisfy the target nest egg. The calculator works in years remaining rather than ages: enter current assets, annual retirement spending, a safe withdrawal rate, an expected return, and how many years are left before retirement. Age fields are not part of it. Financial independence advocates use this tool to determine when they can shift to lower-stress careers.

Enter your current invested assets, annual retirement spending, safe withdrawal rate, expected real return, and years until retirement. The calculator returns your FIRE number, Coast FIRE number, progress, and projected balance.

See also: 401k Calculator, Pay Raise Calculator, and Mortgage Recast Calculator.

Quick Answer

Determine your Coast FIRE number. Enter your current assets, planned retirement spending, withdrawal rate, expected return, and the number of years remaining, to see whether your existing savings can reach the target on growth alone.

$

Stock and bond portfolio earmarked for retirement. Excludes home equity and emergency fund. · e.g. 150,000

$

What you expect to spend per year once you retire, in today's dollars. · e.g. 60,000

%

4% is the classic Trinity-study assumption. · e.g. 4

%

Use a real (inflation-adjusted) return. · e.g. 7

e.g. 25

What Coast FIRE means

Coast FIRE is the portfolio size where, with no further contributions, compound growth alone is expected to reach your full FIRE number by your retirement date. After hitting Coast FIRE you still need to cover current living expenses, but you no longer have to save more for retirement.

Educational projection only. Not financial, tax, retirement, or investment advice. Real returns, inflation, and personal spending all vary.

Coast FIRE

Coast FIRE number

$276,373.77

You need $126,373.77 more to coast to $1,500,000.00 FIRE in 25 years.

Annual retirement spending$60,000.00
FIRE number (4% SWR)$1,500,000.00
Coast FIRE number (today)$276,373.77
Current invested assets$150,000.00
Progress toward Coast FIRE54.3%
Gap to Coast FIRE$126,373.77
Projected balance after 25 yrs (no new contributions)$814,114.90
Years of growth needed to reach Coast FIRE9 yrs

FIRE number = annual spending divided by safe withdrawal rate. Coast FIRE number = FIRE number divided by (1 + return) raised to the years until retirement. Use a real return (return minus inflation) to keep everything in today's dollars.

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Examples

$150k assets · $60k spend · 4% SWR · 7% · 25 yrs

FIRE $1.5M · Coast ≈ $276k · surplus

$50k assets · $50k spend · 4% SWR · 6% · 30 yrs

FIRE $1.25M · Coast ≈ $218k · gap $168k

$300k assets · $80k spend · 3.5% SWR · 7% · 20 yrs

FIRE $2.29M · Coast ≈ $592k · gap $292k

$100k assets · $40k spend · 4% SWR · 7% · 35 yrs

FIRE $1.0M · Coast ≈ $93k · surplus

How it works

Coast FIRE is the portfolio size today that, growing at your expected real return, will equal your full FIRE number by the time you retire, even if you never contribute another dollar.

FIRE number · annual_spending / swr

Coast FIRE number · fire_number / (1 + real_return)^years

Projected balance · current_assets × (1 + real_return)^years

Use a real (inflation-adjusted) return so spending and asset values stay in today's dollars throughout.

Why no contribution limits appear here

Coast FIRE is the point at which you stop contributing and let what you already hold compound to your target. This calculator has no contribution input at all, so annual retirement contribution limits do not enter the result and are not stated. That is a deliberate omission rather than a gap.

They matter on the way to the coast number, not after it. If you are still contributing, the 401k and IRA calculators carry the current limits with the year and the notice that set them.

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Disclaimer. Educational projection only. Coast FIRE assumes a single constant return and ignores sequence-of-returns risk, taxes, healthcare costs, and lifestyle creep. Not financial, tax, retirement, or investment advice.

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Frequently asked questions

Coast FIRE (Financial Independence, Retire Early) is the milestone where your invested assets are projected to grow into your full FIRE number by your target retirement date with no additional contributions. You still work to cover current expenses, but you stop saving for retirement.

Your FIRE number is the portfolio size that supports your retirement spending indefinitely. The standard estimate uses the 4% Safe Withdrawal Rate from the Trinity study: FIRE number = annual spending divided by 0.04 (or 25 times annual spending). Lower SWR assumptions raise the FIRE number; higher SWR assumptions lower it.

Coast FIRE number = FIRE number divided by (1 + expected real return) raised to the number of years until retirement. If you have at least that much invested today, compound growth alone is expected to take you the rest of the way without further contributions.

Use a real (inflation-adjusted) return so the whole calculation stays in today's dollars. Historical long-run real returns for diversified U.S. equity portfolios are roughly 5 to 7%. Balanced portfolios (stocks plus bonds) tend to be a bit lower. Pick a return that matches your asset allocation and risk tolerance.

No. Lean FIRE is a lower spending target (often $25,000 to $40,000 annually). Fat FIRE is a higher spending target ($100,000+ annually). Coast FIRE is a milestone on the path to any FIRE level: it is the point at which you can stop contributing and let compound growth finish the job.

No. Coast FIRE assumes you continue earning enough to cover your current living expenses, you just stop adding to retirement investments. Many Coast FIRE plans reduce work hours, take a lower-paying but more fulfilling job, or focus on a partner's income for living costs while the portfolio compounds.

Barista FIRE typically refers to working a lower-paying, often part-time job (sometimes for benefits like health insurance) once you no longer need to save. Coast FIRE is purely about the portfolio: you have enough invested to reach FIRE without more contributions. The two overlap in practice but emphasize different aspects of the plan.

No. The calculator is a planning estimate. Real returns, sequence-of-returns risk, inflation, taxes, healthcare costs, and personal spending all vary. Consult a qualified financial professional before making retirement decisions.