FIRE Age Calculator: When Can You Retire Early?
The age the income your capital could pay out first covers the spending you want in retirement. Your rent, or your mortgage and the equity behind it, is in the projection too.
- Your FIRE number and FIRE age: the capital your spending requires, and when your own figures reach it.
- Wealth-building projection: track investment growth and saving rate year by year to your FIRE goal.
- Housing integration: factor in mortgage payments, property-value growth and housing equity, or rent.
- Lifestyle planning: set a different retirement spending target to plan for lifestyle changes.
- Saving and withdrawal metrics: saving rates with and without mortgage principal, and what your capital could pay out.
How this calculator works & its assumptions
The calculator projects your finances one year at a time through age 70. Each year it grows your income by your wage-growth rate, your expenses (and rent) by inflation, and your portfolio by your investment return, then adds that year’s savings. It compares the monthly income your capital could safely support against your inflation-adjusted spending requirement, and the age at which the first crosses the second is your estimated FIRE age.
Every figure in the results is in today’s money. The projection runs in future money, then divides each year by inflation compounded to that year, so a balance says what it would buy now rather than what a statement would read then. The growth rates are entered before inflation, so the real gain each year is roughly the rate minus your inflation setting. Worth knowing before you read the results:
- Investment return, inflation and housing growth are treated as constant each year. Real markets vary considerably from year to year.
- Investment return, wage growth and housing growth are entered before inflation, the way a bank or a fund quotes them. The real gain each year is roughly the rate minus the inflation setting.
- Every figure in the results is in today’s money: the projection runs in future money and each year is divided by inflation compounded to that year.
- You are assumed to keep spending the same amount (adjusted for inflation) throughout retirement.
- Tax is simplified to a single withdrawal-tax rate and an optional wealth tax, and may not match your specific situation or future tax law.
That constant, inflation-adjusted withdrawal is a simplification worth stress-testing: backtest your plan against every historical retirement year since 1871 to see how it would have held up through real market crashes and inflation.
Every data source, formula and default across this site is documented on the methodology page.
This calculator is for educational purposes only. Consult a qualified financial professional for advice specific to your situation.
Inputs
Enter your financial details below - results will update automatically
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Select the currency for your calculations
Your age today, the starting point for the projection
Your total monthly income after taxes and deductions
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Current total value of your investment portfolio
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Your total monthly expenses excluding housing costs (rent or mortgage payments are handled separately)
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Annual withdrawal rate from your portfolio in retirement (4% is traditional)
After-tax monthly spending you'll need in retirement, in today's money. The projection grows it with inflation to find your FIRE age
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Expected tax rate on your retirement withdrawals
Do you own or rent?
Current market value of your property
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Current outstanding mortgage balance
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Annual interest rate on your mortgage
Years remaining on your mortgage term
Yearly return on the portfolio before inflation. At 6% return and 2.5% inflation the real return is about 3.4% a year.
Yearly growth of your income before inflation. At 3% growth and 2.5% inflation the real gain is about 0.5% a year.
Yearly rise in prices. Spending, rent and the retirement income target all grow at this rate, and the projection then divides it back out of every figure it reports, so the results read in today's money.
Yearly growth of the property value before inflation. At 5% growth and 2.5% inflation the real gain is about 2.4% a year.
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How is my FIRE age calculated?
It is the first age at which the income your capital could pay out covers the spending you want in retirement. The projection steps forward one year at a time from the age you are now, and the age where the two meet is your FIRE age.
Capital here means everything that could fund a retirement: the invested portfolio plus housing equity, which is what the property is worth less whatever is left on the mortgage. Both sides of that meeting move every year. What the capital could pay out rises as savings and investment returns build the portfolio and as the property grows and the mortgage shrinks behind it, while the spending it has to cover rises with inflation, so the age depends on the whole path rather than on any one year.
Three endings are possible, and the results report all of them with a figure attached. The two can meet inside the projection, which gives an age. They can have met already before it starts, which gives the yearly income to spare. Or the capital’s income can still fall short at the last age projected, which is 70, and that gives how much a year the plan is short by.
How do I calculate my FIRE number?
Divide the yearly spending you want in retirement by your withdrawal rate. At a 4% rate that is the same as multiplying one year of spending by 25, so $40,000 a year needs $1,000,000 before any tax on withdrawals.
This page works from a monthly income target rather than a yearly one, and it grosses the result up for the withdrawal tax rate you set, so the pot is sized against what actually reaches your account rather than what leaves the portfolio. The figure it reports is in today’s money, which is what makes it comparable to a salary you recognise.
The withdrawal rate carries a lot of weight in that division, because it sits in the denominator: halving it doubles the pot. The same $40,000 of spending needs $1,000,000 at 4% and $2,000,000 at 2%. Your spending target is the other half of the same fraction and scales the answer just as directly, which is why a retirement budget you trust is worth more than a precisely argued rate.
Does this calculator include my house and mortgage?
Yes. Your property grows at the housing-growth rate you set, which the results then show after inflation, your mortgage amortises year by year, and the equity between the two counts toward the capital that funds your retirement.
Housing is modelled apart from the rest of your spending, which is why the monthly expenses field leaves it out. For owners, mortgage interest and principal are tracked separately so the balance falling and the equity rising both show up in the projection. For renters, rent has its own field: the model grows it with inflation and adds it to expenses, so typing it into the expenses field as well would count it twice.
The model counts all of your housing equity as spendable capital. A home you live in is not, at least not without selling it, downsizing, or borrowing against it. For anyone who intends to stay put, the portfolio figure on its own is the more conservative read, with the equity behind it as a reserve.
Are the numbers in today’s money or future money?
Today’s money. The FIRE number, the target income and every year of the charts and table are shown at today’s prices. The growth rates on the form are entered before inflation.
The projection itself runs in future money. Income grows at the wage-growth rate, spending and the retirement income target grow at the inflation rate, and the FIRE age is the point where the income that capital could pay out first covers spending. Both sides of that crossing have been inflated by the same number of years, which is what makes the comparison fair, and it lands in the same year whichever way the figures are displayed.
Each figure is then divided by inflation compounded over the years since now, so a balance decades out says what it would buy at today’s prices rather than what a statement would read then. Because the growth rates are entered before inflation, the real gain each year is roughly the rate minus the inflation setting: at the form’s default wage growth and inflation, real progress is about 0.5% a year.
Key FIRE concepts
FIRE, short for Financial Independence, Retire Early, is about saving and investing enough that your portfolio can cover your living costs indefinitely, letting you retire well before the traditional age. These are the ideas the calculator is built on; if you just want a 30-second ballpark before working through them, try the quick FIRE estimate first.
- FIRE number: The total invested capital you need so that your chosen withdrawal rate covers your yearly spending. It is shown in today’s money.
- Withdrawal rate & the 4% rule: The percentage of your portfolio you plan to spend each year in retirement. The widely-cited 4% rule suggests that withdrawing 4% in the first year and adjusting that amount for inflation thereafter has historically lasted a 30-year retirement. A lower rate is safer but needs a bigger portfolio; a higher rate is riskier.
- Saving rate: The share of your net income you save and invest. It sets how much new money enters the portfolio each year. The calculator shows two versions: excluding mortgage principal (pure investing) and including it (total wealth building), since paying down a mortgage also builds net worth.
- Monthly expenses: What you spend each month, with housing left out. Owners leave the mortgage payment out because interest and principal are modelled separately so the tool can track equity, and renters leave rent out because it has its own field. You can set a different spending target for retirement to plan for lifestyle changes.
- Total realizable capital: Your net worth that can actually fund retirement: your investment portfolio plus housing equity (property value minus the outstanding mortgage). This is the figure compared against your FIRE number to estimate your FIRE age.
- Today’s money vs. future money: A figure in today’s money says what it would buy at current prices. The same amount in future money is the larger number a statement would show in that year, once prices have risen. Everything this calculator reports is in today’s money, and the growth rates it asks for are entered before inflation.
If your FIRE number still feels a long way off, you don’t have to wait for full financial independence to change your life. The lifestyle change calculator models how a career break, sabbatical, or working part-time earlier affects your timeline, and the coast FIRE calculator answers the milestone that arrives well before this one: the balance that would reach your target on its own if you stopped contributing today.
Frequently asked questions
Is the 4% rule a safe withdrawal rate?
The 4% rule comes from the Trinity study and has historically sustained a 30-year retirement in the US, but it is a guideline, not a guarantee. Early retirees planning for 40–50 years, or those worried about a weak market early in retirement, often choose a more conservative 3–3.5%. You can set any withdrawal rate in the calculator to see the effect on your FIRE number and FIRE age. The retirement probability calculator computes the exact odds a given rate carries, from the full return distribution.
Why does my saving rate matter so much?
It sets how much new money enters the portfolio every year, and the projection is most sensitive to that early on, while the balance is still small enough that contributions outweigh returns. This page keeps your retirement target as a separate input, so raising your saving rate moves your FIRE age without moving your FIRE number. Outside the model the two are linked, because living on less both frees up more to invest and lowers the pot that has to cover the rest. The calculator reports two saving rates: one excluding mortgage principal, which is pure investing, and one including it, since paying down a mortgage builds net worth too. The savings rate calculator turns that same share into a number of years until financial independence.
Can I use this to plan Coast FIRE or Barista FIRE?
Use the coast FIRE calculator instead. Coast FIRE asks a different question: what balance today would grow into your target on its own with nothing further added, rather than what you need in total. That tool answers it directly, and its barista mode covers the case where part-time income pays for some of your spending and the portfolio funds the rest. This page is the full projection, from where you are now to the age your capital crosses your requirement.
What is the difference between lean FIRE and fat FIRE?
Lean FIRE and fat FIRE aren’t different modes here, they’re different monthly retirement income targets run through the same FIRE-number arithmetic: a smaller target sizes a smaller FIRE number, a larger one sizes a larger one. The FIRE community broadly calls a bare-bones retirement budget lean and a comfortable or lavish one fat, but those are informal conventions rather than fixed definitions, so the more useful step is entering your own lean and fat targets here and comparing the FIRE age each one produces.