Input help · Result interpretation
Make sense of your Coast FIRE calculator result
If a number looks unexpected, first check what it measures. Your current Coast target, portfolio balance, retirement target and projected date answer different questions.
Start with these five input checks
Copy these values from both models before comparing results. Small differences over a long horizon can create a substantial difference in the target.
| Check | Match this input | Why it matters |
|---|---|---|
| Timeline | Current age and retirement age | A shorter growth horizon usually needs a larger starting balance when the modeled real return is positive. |
| Spending | Annual spending in today’s dollars | Monthly expenses entered as annual spending can make the target much too small. Multiply a monthly budget by 12 first. |
| Investments | Assets included in your retirement model | A net-worth figure can include a home or money reserved for near-term costs that is not available to compound in this portfolio. |
| Rates | Nominal return, inflation, annual fees and withdrawal rate | Match all four inputs when comparing calculators. The same displayed return can mean nominal growth on one site and real growth on another. |
| Contributions | Whether the projected path includes new deposits | The basic Coast target assumes no new retirement deposits; the date projection can include a monthly contribution. |
A reproducible baseline
Check the math with one example
At age 30, with retirement at 65 and $50,000 in annual spending, a 4.00% withdrawal-rate assumption gives a retirement target of $1,250,000.
The main model’s 7.00% nominal return, 3.00% inflation and 0.10% annual fees produce about 3.79% real return. Discounting the retirement target over 35 years gives a current Coast target of $340,403, using the unrounded rate.
A $200,000 starting portfolio leaves a modeled gap of $140,403. Changing only that balance changes the gap; it does not change the required target.
Load this example from the homepage →Why does changing my current investments leave the Coast FIRE number unchanged?
The target is the amount required by your spending, retirement horizon and assumptions. Current investments are compared with that target; they are not an input to the target formula. Raising your balance should reduce the gap and increase projected portfolio value, even when the required target stays the same.
Why do monthly contributions change the date but not the current target?
The Coast FIRE test asks whether today’s invested amount could grow to a later retirement target with no additional contributions. A contribution projection asks when you could reach that threshold by continuing to save. These are different calculations. On the homepage, open “Project a Coast FIRE date” to include monthly deposits in the projected path.
Why do two Coast FIRE calculators give different answers?
Check the inputs in the table above, including fees and the definition of spending. Then check the formulas: some tools use nominal dollars, some inflation-adjusted dollars, and some offset pension income differently. Monthly contribution timing and rounding can also change projected dates. A larger discrepancy should be traced to assumptions before treating either result as interchangeable.
Should I inflate my spending before entering it?
For the main calculator, enter annual retirement spending in today’s purchasing power. The model separately adjusts investment growth for inflation. Entering a future inflated budget into that model while also applying its inflation adjustment mixes two dollar bases and raises the target beyond the intended comparison.
Do I enter 7 or 0.07 for a 7% return?
Enter 7 in the main calculator’s percentage field. It converts that display value into 0.07 for the formula. The same convention applies to its inflation, annual fee and withdrawal-rate fields. The nominal return is before the inflation adjustment and the separate fee input.
Why can the Coast target equal or exceed the retirement target?
At zero real return, compounding adds no purchasing power, so the current target equals the retirement target. At a negative real return, the modeled portfolio loses purchasing power over time, so the current amount required can be larger. A positive nominal return can still produce a negative real return after inflation and fees.
What if the model does not reach Coast FIRE by my retirement age?
A projection can end below its target. The end of the timeline is not evidence that Coast FIRE has been reached. The homepage date panel identifies this outcome as “Not reached by retirement.” Compare contribution levels, spending or retirement timing to see how the modeled shortfall changes.
Why does the homepage reject my age or spending input?
The homepage requires a current age from 18 to 80, a retirement age from 30 to 100 that is greater than current age, nonnegative investments and annual spending from $1,000 to $1 million. A message next to a field explains a value outside those limits. These are interface limits, not definitions of who can pursue Coast FIRE.
Should emergency cash, my home and education savings count as investments?
The main model compounds the balance you enter as one retirement portfolio. It does not separately model a home sale, a cash reserve or an education withdrawal. Counting money you plan to spend soon as long-term invested capital can overstate the amount remaining to grow.
Why does a pension or benefit change the target differently from my estimate?
Income amount and start age both matter. A payment that begins later cannot cover earlier spending. Specialized income and advanced models also make assumptions about how income offsets portfolio-funded spending. Check the modeled start age, whether amounts share the same purchasing-power basis, and the page’s methodology.
Does reaching the modeled target mean I can quit working or stop all saving?
The threshold compares investments with a future retirement goal under fixed assumptions. It does not supply current living expenses, cash for a work break or a reserve for unexpected costs. It also does not ensure accessible account balances when spending starts. Working less, pausing contributions and retiring immediately require different cash-flow comparisons.
Does the calculator predict market returns or a probability of success?
The main calculator projects growth at a selected rate. That is a deterministic scenario, not a forecast or a probability estimate. A smooth line does not simulate changing markets, every tax rule or unexpected household events. Comparing lower-return scenarios shows sensitivity; it still does not assign a probability to them.
Need a different scenario?
The question finder covers every live tool, including family costs, work changes, career models, countries and income or spending amounts.
Browse all calculator questions →For an unexplained result, you can suggest a question. Include the input values, the result you saw and what you expected, without account numbers or other identifying financial details.