Stop-at-coast planning, not a retirement guarantee Coast FIRE asks how much you need invested today so compound growth alone could carry that balance to your retirement target by the chosen age. It is a planning shortcut built on constant-return and withdrawal assumptions, not a promise of retirement readiness.
What this calculator shows
It estimates your target FIRE portfolio, discounts that target back to today using the chosen return assumption, and compares the result with your current invested balance. If your current savings already exceed the discounted target, you have mathematically reached Coast FIRE under these assumptions.
Coast FIRE result
$117,078.67
Amount needed today so growth alone could reach $1,250,000.00 by age 65, assuming 7% annual growth and a 4% withdrawal rule.
FIRE number
$1,250,000.00
Projected current balance
$1,067,658.15
Projected with contributions
$1,923,364.96
Years to retirement
35
Coverage of target
85.41%
Gap remaining
Need $17,078.67 more invested now.
Current balance would grow by about 10.68x before retirement under the selected return assumption.
Contribution runway
If you keep investing $500.00 per month, this model estimates reaching Coast FIRE around age 33.25.
Coast FIRE planning sheet
Metric
Value
Why it matters
Withdrawal rule used
4%
The FIRE target is annual expenses divided by the assumed withdrawal rate.
Target FIRE number
$1,250,000.00
Portfolio size needed at retirement to support the chosen annual spending target under this rule.
Coast FIRE number today
$117,078.67
Amount needed right now so growth alone reaches the target by the retirement age.
Projected value of current savings
$1,067,658.15
Value your current balance would reach by retirement if no new money were added.
Projected value if contributions continue
$1,923,364.96
Value by retirement if the monthly contribution is invested until the selected retirement age.
Estimated coast age with contributions
33.3
Approximate age when current savings plus continued monthly investing first cross the shrinking Coast FIRE threshold.
Coverage of Coast FIRE target
85.4%
How much of the required Coast FIRE number is already covered by the current balance.
Additional amount needed now
$17,078.67
One-time amount needed today to reach the Coast FIRE threshold under the selected assumptions.
Sequence risk and spending changes are not modeled Coast FIRE is sensitive to the chosen return assumption, future spending, inflation, taxes, and the withdrawal rule. Treat the result as a planning checkpoint, not a guarantee that contributions can safely stop.
Coast FIRE Calculator: how much invested now could coast to retirement
A Coast FIRE plan asks a narrower question than full financial independence: if you stopped making retirement contributions today, how much would you need invested already so long-term market growth alone could still carry that balance to your retirement target by the age you choose? This calculator estimates that threshold using your spending target, retirement age, expected return, and withdrawal assumption.
What Coast FIRE means
Coast FIRE is a planning milestone, not a retirement date by itself. It means your current invested balance is large enough that, under a chosen long-run return assumption, it could grow to your target retirement portfolio without additional contributions. You may still need to keep working for living expenses, insurance, or other goals before retirement.
That distinction matters because Coast FIRE is usually about contribution flexibility, not full work optionality right now. Reaching the threshold can mean you are no longer mathematically dependent on future retirement contributions under the model, but it does not guarantee your spending, taxes, or market path will behave the way the model assumes.
How the calculator works
The calculator first estimates a target FIRE portfolio by dividing annual expenses by the chosen withdrawal rule. It then discounts that target back to today using the assumed annual return and the number of years until retirement. The discounted figure is the Coast FIRE number: the amount you would need invested now so growth alone could reach the target by retirement age.
It also projects what your current savings would grow to by retirement under the same return assumption. Comparing that projection with the target shows whether you are already above the Coast FIRE threshold or whether a one-time gap still remains under the model.
Target FIRE number = annual expenses / withdrawal rate
Turns desired retirement spending into an estimated portfolio target under the chosen withdrawal rule.
Coast FIRE today = target FIRE number / (1 + return)^years
Discounts the retirement target back to the present using the selected annual return assumption.
Contribution runway: when could you stop saving for retirement?
Many Coast FIRE searches are not only asking whether the user has reached the threshold today. They are asking how long they might need to keep saving before they can let the portfolio coast. The monthly contribution field answers that practical follow-up by projecting current savings plus continued monthly investing, then checking when that projected balance first crosses the shrinking Coast FIRE threshold.
This runway view is still conservative in an important way: the headline Coast FIRE number remains the no-further-contributions threshold. The contribution result is a second scenario for people who expect to keep adding money for a while and want to estimate a possible coast age. It can help compare a lower-stress saving plan, a part-time work transition, or a pause in retirement contributions against the original stop-saving-today result.
The model assumes the same return for the contribution runway and the final coasting period. That keeps the calculator understandable, but it also means the output is sensitive to a single return assumption. A lower assumed return usually pushes the coast age later, while a higher return can make the runway look shorter than a real sequence of market returns would justify.
Projected balance after each month = prior balance × (1 + monthly return) + monthly contribution
Adds the optional contribution runway before checking whether the projected balance has crossed the Coast FIRE threshold.
Coast target at a future month = FIRE target / (1 + monthly return)^months remaining
Recalculates the shrinking Coast FIRE threshold as the retirement date gets closer.
Where the assumptions can break down
Coast FIRE models are highly sensitive to return assumptions, inflation, spending changes, taxes, investment fees, and the withdrawal rule. A small change to the assumed return or withdrawal rate can materially change the threshold, especially when retirement is decades away.
Sequence risk also matters. Real markets do not deliver a steady annual return every year, and the retirement years themselves can be affected by prolonged weak returns, changing spending needs, healthcare costs, or delayed benefit decisions. That is why a Coast FIRE result should be used as a planning checkpoint rather than a promise that contributions can safely stop forever.
Worked example
If you expect to spend 50,000 per year in retirement and use a 4% withdrawal rule, the target portfolio is 1,250,000. If retirement is 35 years away and you assume 7% annual growth, the Coast FIRE threshold today is the present value of that target, which is much lower than 1,250,000 because of the long growth runway.
That is why Coast FIRE can be reached long before full FIRE. The tradeoff is that the result depends on patient long-term compounding and on the assumption that future spending and withdrawal conditions will still support the model when retirement arrives.
Frequently asked questions
Is Coast FIRE the same as being financially independent right now?
No. Coast FIRE only means your current invested balance may be large enough to grow to your retirement target without further retirement contributions. It does not mean you can already stop working and cover current living expenses indefinitely.
Why does the withdrawal rule matter so much?
Because it sets the target portfolio size. A lower withdrawal assumption implies a larger target portfolio, which pushes the Coast FIRE number higher today. A higher withdrawal assumption does the opposite, but it also assumes a more aggressive retirement drawdown.
Does Coast FIRE include inflation automatically?
Not by itself. The calculator uses the return and withdrawal assumptions you enter. If you want an inflation-aware result, your spending target and return assumption should be chosen consistently, such as using real-return thinking rather than mixing nominal and inflation-adjusted numbers.
What if I still plan to keep contributing after I hit Coast FIRE?
Then the model is conservative relative to your actual plan. Coast FIRE asks what happens if contributions stop. If you continue contributing, your projected retirement balance could exceed the threshold under the same assumptions.
How does the monthly contribution runway work?
The calculator keeps the main Coast FIRE number as the amount needed today with no further retirement contributions. The optional monthly contribution field then runs a second scenario: it grows your current balance with monthly investing and checks when that balance first crosses the Coast FIRE threshold for the remaining time to retirement.
Can I use this as a Barista FIRE or semi-retirement calculator?
Only as a rough contribution-flexibility checkpoint. Coast FIRE focuses on whether invested assets can grow to a future retirement target. Barista FIRE, semi-retirement, and part-time work plans also need current cash flow, health insurance, taxes, benefits, and employment-risk assumptions that this calculator does not model.
Should I use a real or nominal return assumption?
Use assumptions consistently. If annual expenses are stated in today's purchasing power, a real return assumption can make the result easier to interpret. If you use a nominal return, remember that the future portfolio target and projected balance are nominal-style model outputs and inflation may reduce purchasing power.
