Coast FIRE Calculator
Calculate your Coast FIRE number — how much you need invested today so growth alone reaches your FIRE number by retirement age, with no more contributions required.
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Adjust values to see instant results
Additional Details
Your Coast FIRE Number
Estimated • Based on your inputs
Surplus (or Gap) vs. Coast Number
-$43,663.00
Detailed Breakdown
Growth Over Time
Disclaimer: This calculator provides estimates for informational purposes only. Results should not be considered financial, tax, or legal advice. Consult a qualified professional for your specific situation.
How This Calculator Works
Calculation methodology and assumptions
Coast FIRE number = full FIRE number ÷ (1 + expected annual return)^(years until retirement). It represents the invested-asset balance you'd need right now so that compound growth alone — with zero further contributions — reaches your full FIRE number (annual retirement expenses ÷ safe withdrawal rate) by your target retirement age. If your current invested assets already exceed your Coast FIRE number, you've reached Coast FIRE: you can stop saving for retirement and still hit your number through growth alone (though you'd still need to cover current living expenses). If not, this calculator projects how many years of your current monthly contribution it will take to close the gap, after which it models growth-only compounding to retirement.
How to Use This Investment & Retirement Calculator
- 1
Fill in Current Age, Target Retirement Age and Annual Expenses in Retirement
Current Age starts at 30; Target Retirement Age starts at 65; Annual Expenses in Retirement starts at $40,000. Replace each one with your own figure.
- 2
Fill in Safe Withdrawal Rate (SWR), Expected Annual Return and Current Invested Assets
Safe Withdrawal Rate (SWR) starts at 4%; Expected Annual Return starts at 7%; Current Invested Assets starts at $50,000. Replace each one with your own figure.
- 3
Fill in Current Monthly Contribution
Current Monthly Contribution starts at $500. Replace it with your own figure.
- 4
Read the results
The calculator leads with Your Coast FIRE Number and Surplus (or Gap) vs. Coast Number, followed by 5 supporting figures.
Example Calculation
What the calculator above returns before you change anything: age 30, retiring at 65, $40,000 of yearly spending in retirement, a 4% withdrawal rate, a 7% return and $50,000 invested.
The full target is $40,000 ÷ 4% = $1,000,000. The Coast FIRE number is that target discounted back over the 35 years to retirement: $1,000,000 ÷ 1.07^35 = $93,663.
Result: Coast FIRE number today: $93,663. With $50,000 invested you are $43,663 short of it (53.38% of the way). The number rises every year you wait, because fewer years of growth remain.
What Affects Your Results
Rate of Return
Even small differences compound massively over time. 7% vs. 8% over 30 years on $100K means a difference of $200K+. Asset allocation drives your expected return.
Time Horizon
Compounding accelerates exponentially. Most of your wealth is generated in the final years — a 30-year investment earns more in its last 5 years than its first 15.
Contribution Consistency
Regular monthly investments (dollar-cost averaging) smooth out market volatility and ensure you're always buying — including during dips when prices are low.
Fees & Expenses
A 1% annual fee vs. 0.1% fee on a $500K portfolio costs you $4,500/year extra. Over 30 years, high fees can consume 25–30% of potential returns. Use low-cost index funds.
Tips & Best Practices
- Start early. Thanks to compounding, $200/month invested from age 25 to 65 at 8% returns grows to ~$700K. Waiting until 35 cuts that to ~$300K — a $400K penalty for the 10-year delay.
- Don't try to time the market. Research consistently shows that time in the market beats timing the market. Missing the 10 best trading days over 20 years can halve your returns.
- Consider tax-advantaged accounts first: 401(k) (especially with employer match), IRA, HSA. These reduce your tax drag — a 25% tax bracket investor keeps more in a tax-deferred account.
- Rebalance annually. If stocks outperform and grow from 80% to 90% of your portfolio, rebalancing back to 80% locks in gains and manages risk.
- Factor in your state's tax treatment of investment income. Some states exempt certain investment income or have lower rates on capital gains.
StateCalc Team
Editorial Team
The StateCalc team builds financial calculators using data from official government sources including the IRS, U.S. Census Bureau, BLS, and state revenue departments. All formulas are validated by an automated test suite and cross-referenced against published data.
Our editorial standardsFrequently Asked Questions
What is Coast FIRE?
Coast FIRE is the point at which you've invested enough that, even if you never contributed another dollar to retirement, compound growth alone would carry your balance to your full FIRE number by your target retirement age. Once you hit your Coast FIRE number, you can "coast" — you still need to earn enough to cover current living expenses, but you no longer need to save for retirement specifically.
How is the Coast FIRE number calculated?
Coast FIRE number = FIRE number ÷ (1 + r)^n, where r is your expected annual return and n is the number of years until your target retirement age. It's the reverse of a standard future-value compounding calculation: instead of asking "what will this grow to," it asks "how much do I need today to grow to that target."
Coast FIRE vs. regular FIRE — what's the difference?
Regular FIRE targets accumulating your full FIRE number (25x expenses) so you can stop working and live off withdrawals immediately. Coast FIRE is an earlier, less extreme milestone — once reached, you can stop retirement saving and shift focus to covering current expenses (often by working fewer hours, taking a lower-stress job, or pursuing other goals), while your existing investments compound untouched until your target retirement age.
Does Coast FIRE mean I can stop working entirely?
No — Coast FIRE only means you can stop saving specifically for retirement. You still need income to cover your current living expenses until you reach your target retirement age (or full FIRE), since Coast FIRE assumes no withdrawals from your invested assets until then.
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