Coast FIRE Date Calculator
Estimate the first month and year when your projected portfolio may reach the Coast FIRE amount required for your remaining time until retirement.
Your Details
Results update live as you type
Real Return (after inflation & fees)
3.79% per year
Estimated Coast FIRE Date
Not ReachedAt the current contribution rate, the projected shortfall at retirement is $385,667 against a $1,000,000 target.
Coast FIRE Threshold
$1,000,000
not reached
Coast FIRE Age
N/A
Coast FIRE Date
Not Reached
Time Until Coast
—
Projected at Retirement
$614,333
Portfolio Growth and Coast FIRE Threshold
Age 30 → 65 · Hover for details
| Age | Modeled portfolio value | Modeled Coast FIRE target |
|---|---|---|
| 30 | $50,000 | $272,322 |
| 35 | $93,128 | $327,933 |
| 40 | $145,063 | $394,901 |
| 45 | $207,604 | $475,544 |
| 50 | $282,916 | $572,655 |
| 55 | $373,607 | $689,597 |
| 60 | $482,819 | $830,420 |
| 65 | $614,333 | $1,000,000 |
Chart summary: Portfolio does not cross the Coast FIRE threshold before retirement age 65. Estimated shortfall: $385,667.
Reach Coast FIRE by a Target Date
Slide to a target age — see the required monthly contribution.
Required Monthly Contribution
$2,207
to coast by age 40
vs Current Plan
+$1,707
more per month needed
Coast Requirement at 40
$396,126
needed to coast from age 40
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How to Use the Calculator
Three simple steps to your estimated Coast FIRE crossing date.
Enter your age and retirement goal
Set your current age, retirement age and current invested assets. These define the projection horizon and your Coast FIRE threshold.
Add your monthly contribution
Enter how much you invest each month. This determines how fast your portfolio grows toward the Coast FIRE threshold.
Review your estimated Coast FIRE date
The dominant result shows the first month your portfolio may reach the Coast FIRE threshold. The graph plots the full projection.
What the Coast FIRE Date Means
It estimates the first month the projected portfolio reaches the Coast FIRE threshold — the point where compound growth alone may cover your retirement goal without further contributions.
The calculation uses current investments, monthly contributions and compound growth applied month by month from your current age to retirement.
The required Coast FIRE amount changes each month because fewer growth years remain as retirement approaches — this is why the threshold line trends upward on the chart.
This is a projection, not a guaranteed date. Actual returns, fees, inflation and personal decisions will differ from the constant assumptions used here.
How the Calculation Works
Four formulas applied in sequence every month of the projection.
Retirement Target
Retirement Target = Annual Spending ÷ Withdrawal Rate
Divides your planned annual spending by the safe withdrawal rate (e.g. 4%) to find the total portfolio needed at retirement. Example: $40,000 ÷ 0.04 = $1,000,000.
Real Return
Real Return = ((1 + Nominal Return − Fees) ÷ (1 + Inflation)) − 1
The net annual growth rate after investment fees and inflation. Example: ((1 + 0.07 − 0.001) ÷ (1 + 0.03)) − 1 ≈ 3.79% per year real.
Coast FIRE Requirement
Coast Requirement = Retirement Target ÷ (1 + Real Return)^Years Remaining
The amount needed today (at a given age) for compound growth alone to reach the retirement target. Recalculated every month — rises as years remaining shrink.
Estimated Coast FIRE Date
Coast Date = First month where Projected Portfolio ≥ Coast Requirement
The exact calendar month and year when the monthly projected balance first meets or exceeds the age-adjusted Coast FIRE requirement.
Factors That Change Your Coast FIRE Date
The primary variables that move the projected crossing point earlier or later.
Current Invested Assets
A larger starting balance gives compound interest more capital to work with, potentially moving the estimated date earlier.
Monthly Contribution
Higher contributions grow the portfolio faster during the contribution period and may cross the moving threshold earlier.
Retirement Age
A later retirement age provides more compounding time and typically reduces the age-adjusted threshold required at any given point.
Annual Retirement Spending
Higher planned spending increases the full retirement target and raises the threshold the portfolio must cross at every age.
Real Return Rate
The nominal return after inflation and investment fees — drives both portfolio growth and discounting of the future retirement target.
Safe Withdrawal Rate
A lower withdrawal rate (e.g. 3.5% instead of 4%) creates a larger full retirement target and raises the threshold at every point.
Use the Right Calculator for the Next Question
Move between the main calculator, focused tools, and plain-English guides without changing the site experience.
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Main Coast FIRE Calculator
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Coast FIRE Calculator for Couples
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Coast FIRE Date Calculator
ToolSee the timeline to Coast FIRE and test how changing your contribution affects the crossing date.
Coast FIRE Calculator with Pension
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Related Guides
Coast FIRE Calculator Troubleshooting
GuideUnderstand unexpected Coast FIRE results: unchanged targets, inflation, contributions, return assumptions, input errors and differences between calculators.
What Is Coast FIRE?
GuideA complete introduction to Coast FIRE — what it means, how it works, and why it matters for your financial independence journey.
How Coast FIRE Works
GuideUnderstand the three phases of Coast FIRE: Build, Coast, and Retire. Learn how compound growth does the heavy lifting.
Coast FIRE Formula Explained
GuideLearn the Coast FIRE formula in simple terms. See what each number means, follow an easy example, and understand why age, return, inflation, and retirement spending change the result.
Frequently Asked Questions
How is my Coast FIRE date calculated?
The calculator projects your portfolio month by month, growing it using compound interest and monthly contributions. Each month it compares the projected balance with the age-adjusted Coast FIRE requirement at that point in the timeline. The first month the projected balance meets or exceeds that moving requirement becomes the estimated Coast FIRE date.
Why does my Coast FIRE requirement change over time?
The age-adjusted Coast FIRE requirement depends on how many years remain until retirement. As the timeline shortens, the portfolio has fewer years of compound growth available, so the amount required at each point generally rises. This is why the threshold line on the chart trends upward as retirement approaches.
What happens if the portfolio never reaches the target?
If the projected portfolio does not reach the age-adjusted threshold before retirement, the calculator shows "Not Reached Before Retirement". It then displays the projected retirement balance, the full retirement target, and the estimated shortfall. No estimated Coast FIRE date or "time until Coast FIRE" is shown in this state.
Can I calculate the contribution required for a target Coast FIRE age?
Yes. Use the "Reach Coast FIRE by a Target Date" section directly below the calculator. Drag the slider to your target age and the tool uses a binary-search approach to estimate the exact monthly contribution required to reach Coast FIRE by that age.
How does increasing monthly contributions affect the date?
Higher contributions grow the portfolio faster during the contribution phase, which can move the estimated Coast FIRE date earlier. You can model a rising savings rate using the Annual Contribution Increase field inside the "Change assumptions" accordion.
Is the estimated Coast FIRE date guaranteed?
No. The calculator provides an educational planning estimate based on constant nominal return, inflation, and fee assumptions. Actual investment performance, sequence-of-returns risk, taxes, and personal decisions will affect real-world outcomes. It is a projection, not a prediction or financial advice.
Verified Sources & Methodology
IRC Sec. 72(t)(2)(A)(v) Early Distribution Exception
2026 Federal Brackets & Standard Deductions
Summary Plan Description (SPD) Distribution Rules
Retirement Claiming Ages (62–70)