Worked scenarios
Coast FIRE examples by age
By the Coast FIRE Calculator editorial team · Calculation methodology
Age changes the time your investments have to grow; savings determine whether you have already crossed the target. Those are different inputs. The examples below use the same retirement budget and rates so that the effect of age remains visible. They are fictional planning scenarios, not customer results, average balances or recommendations.
One budget, three different starting points
The shared budget is $48,000 a year in today's USD, with retirement at 65. Dividing spending by the assumed 4% withdrawal rate produces the same full FIRE target of $1,200,000 in all three cases. The Coast target discounts that future target to each person's current age. Current savings do not change the target; they change the gap to it.
The assumed 7% nominal return and 3% inflation imply 3.8835% real growth, calculated as (1 + nominal return) ÷ (1 + inflation) − 1. All dollar outputs here are evaluated at build time by the same functions as our Coast FIRE calculator, with further contributions set to zero. Amounts are rounded to whole dollars only for display.
Worked examples
Three illustrative scenarios, not reports of real investors. All retire at 65, spend $48,000 a year in today's USD, assume 7% nominal growth, 3% inflation and a 4% withdrawal rate. No further contributions are included. These fixed examples are separate from interactive calculator inputs.
Age 30 · $250,000 invested
- Coast target today
- $316,266
- Full FIRE target at retirement
- $1,200,000
- Additional invested amount needed today
- $66,266
Below the Coast target. With no further savings, this scenario does not reach the retirement target.
Age 35 · $400,000 invested
- Coast target today
- $382,635
- Full FIRE target at retirement
- $1,200,000
- Additional invested amount needed today
- $0
Already above the Coast target under these assumptions. Current living expenses still need separate income.
Age 40 · $500,000 invested
- Coast target today
- $462,932
- Full FIRE target at retirement
- $1,200,000
- Additional invested amount needed today
- $0
Already above the Coast target under these assumptions. Current living expenses still need separate income.
See the age-by-age calculations and interpretation or compare Coast FIRE with Barista FIRE. Values are generated at build time from our calculator functions and rounded only for display. See methodology for model boundaries.
What each result means
Starting at 30 with $250,000
There are 35 years until the assumed retirement date. The Coast target is $316,266. With no more contributions and constant real growth, the entered balance projects to $948,570 at retirement, compared with the $1,200,000 full target.
This starting balance is below the threshold by $66,266 today. The gap is an immediate invested-asset shortfall, not a monthly contribution recommendation. Contributions made later have less time to compound; use the interactive calculator to solve that separate timeline.
Starting at 35 with $400,000
There are 30 years until the assumed retirement date. The Coast target is $382,635. With no more contributions and constant real growth, the entered balance projects to $1,254,459 at retirement, compared with the $1,200,000 full target.
This starting balance exceeds the Coast threshold. That means the retirement target is reached in this model without additional saving, not that current living costs can be paid from this portfolio immediately. Income outside the portfolio still covers spending during the coast period.
Starting at 40 with $500,000
There are 25 years until the assumed retirement date. The Coast target is $462,932. With no more contributions and constant real growth, the entered balance projects to $1,296,086 at retirement, compared with the $1,200,000 full target.
This starting balance exceeds the Coast threshold. That means the retirement target is reached in this model without additional saving, not that current living costs can be paid from this portfolio immediately. Income outside the portfolio still covers spending during the coast period.
A younger age does not guarantee an easier plan
The younger scenario has more compounding years and therefore the lowest Coast target. But it also starts with a smaller portfolio. An older person can be above a higher target while a younger person remains below a lower one. Compare invested assets with the target for your own age rather than choosing the smallest number in the table.
These balances represent money left invested for retirement. A home, emergency reserve or money earmarked for a near-term purchase is not automatically available to compound under the same assumptions. The tool does not decide which assets qualify, apply account-specific withdrawal restrictions or reconcile different tax treatments. Keep your input definition consistent before comparing scenarios.
Stress the assumptions before stopping contributions
For the age-30 case, changing only nominal growth from 7% to 5% raises the Coast target from $316,266 to $612,151. This is a sensitivity comparison, not a prediction that either rate will occur. Inflation and investment costs reduce purchasing power; a smooth return does not reproduce market losses arriving early or late.
Changing only annual spending to $60,000 gives a full target of $1,500,000 and an age-30 Coast target of $395,332. A budget change can invalidate a previous “achieved” result even when the account balance has not fallen. Recheck spending, retirement age and assumptions together rather than treating a threshold crossing as permanent.
What this comparison leaves out
The withdrawal rate is an editable model input, not an official safe rate. We do not simulate taxes, health coverage, account-access penalties, historical success rates or separate pension start dates. The full retirement budget remains portfolio-funded throughout this example. If Social Security or a pension starts later, subtracting it from every retirement year would hide the intervening funding gap.
If the aim is to use part-time earnings and portfolio withdrawals now, rather than let the portfolio grow untouched, see Coast FIRE vs Barista FIRE and the Barista FIRE calculator. For a separate spending-down scenario, use the retirement withdrawal calculator.
Official sources and reproducibility
- SEC Investor.gov: Compound Interest Calculator — official context for principal, contributions, years and assumed growth, not endorsement of our Coast targets.
- SEC Investor.gov: Risk and Return — investment risk, inflation and purchasing power.
The arithmetic uses calculateAllResults and projectPortfolioAtRetirement in fire.ts. These functions explain the model; no government publication defines a personal Coast FIRE entitlement. Corrections: hello@coastfirecalculator.io.