Coast FIRE Calculator
Find your Coast Number and the age you can stop contributing and still retire on time
Coast FIRE Settings
Set to 0 to model stopping contributions today.
Coast FIRE Results
Gap to Reach Coast FIRE Today
$68.17K
Projected Coast FIRE age: 59.1 (with current contributions)
FIRE Number
$1.20M
Coast Number (Today)
$98.17K
If You Stop Contributing Today
$366.71K
at age 65
If You Keep Contributing
$1.24M
at age 65
Complete Guide to Coast FIRE
What is Coast FIRE?
Coast FIRE is a milestone within the Financial Independence, Retire Early movement. It marks the point where your existing investments, given enough time and market growth, will compound into your full retirement number without another dollar of new contributions. From that point forward, you can "coast" — covering current living expenses from income while your portfolio does the rest of the work.
It is a different question from the standard FIRE Calculator, which assumes you keep saving until you hit your number. Coast FIRE instead asks: given what is already invested, how much longer until saving becomes optional? Once you know your Coast Number, pair it with the Retirement Savings Calculator to model a full retirement income plan.
Formula
Coast FIRE Number:
FIRE Number = Annual Retirement Expenses / Withdrawal Rate
Coast Number (Today) = FIRE Number / (1 + r)^Years to Retirement
Reached Coast FIRE if: Current Savings >= Coast Number (Today)
Where: r is your expected annual investment return, and Years to Retirement is your target retirement age minus your current age. The Coast Number is the amount you need invested right now, with zero further contributions, to grow to your FIRE Number by retirement.
Benefits
Career Flexibility
Once you coast, you can downshift to lower-paying but more fulfilling work without derailing retirement.
Clear Milestone
A concrete Coast Number turns a vague long-term goal into a specific dollar figure you can track.
Time-Value Insight
Shows exactly how much compounding, not new savings, can do the remaining work for you.
Two Scenarios at Once
Compare stopping contributions today against continuing them, side by side.
Tips
Tip 1: Use a conservative return rate (6-7% real) rather than a recent bull-market average — Coast FIRE plans span decades and need to survive multiple market cycles.
Tip 2: Recalculate every year — your Coast Number changes as your age, expenses, and portfolio balance all move.
Tip 3: Even after reaching Coast FIRE, keep some cash buffer — check your Emergency Fund stays fully funded before scaling back income.
Common Mistakes
Overestimating Returns
A too-high return rate makes the Coast Number look artificially reachable, leading to under-saving.
Ignoring Inflation on Expenses
Annual expenses tend to rise over decades; recheck the FIRE Number periodically rather than locking it in once.
Treating Coast FIRE as Full Retirement
Reaching Coast FIRE means you can stop investing more, not that you can stop earning income entirely before your target retirement age.
Related tools
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OpenFrequently Asked Questions
What is Coast FIRE?
Coast FIRE is the point at which your current investments, left alone with no further contributions, will grow through compound returns to your full Financial Independence (FIRE) number by your target retirement age. Once you hit it, saving more becomes optional rather than required.
How is the Coast FIRE number calculated?
Coast Number Today = FIRE Number / (1 + r)^Years to Retirement, where FIRE Number = Annual Retirement Expenses / Withdrawal Rate and r is your expected annual investment return. If your current savings meet or exceed this discounted number, you have reached Coast FIRE.
How does this compare to the FIRE Calculator?
The FIRE Calculator solves for your standard, Lean, and Fat FIRE numbers assuming you keep saving a fixed percentage of income until you hit them. This tool answers a narrower question: given what you have saved right now, at what age could you stop contributing entirely and still reach your goal on time.
What are common mistakes people make with Coast FIRE?
The most common errors are using an overly optimistic return rate that ignores sequence-of-returns risk, forgetting that Coast FIRE assumes zero further contributions (a partial pullback is not the same thing), and confusing the Coast Number today with the full FIRE Number, which is a much larger figure.
Are there tax or regulatory considerations?
Coast FIRE math is currency- and jurisdiction-agnostic, but real portfolios usually mix taxable, tax-deferred (401k/traditional IRA), and tax-free (Roth) accounts. Early access to tax-deferred accounts before typical retirement ages may trigger penalties, so factor account type into how early you can actually draw down funds.
Worked example?
A 28-year-old with $30,000 saved, contributing $400/month, targeting $48,000/year in expenses at a 4% withdrawal rate (a $1.2M FIRE Number) and a 7% annual return has a Coast Number today of about $98,171. They are not there yet, but at the current contribution rate they reach Coast FIRE around age 59.1, and are still on track to hit the full $1.2M FIRE Number by 65 if they keep contributing.