FIRE Number Calculator
Find the portfolio you need to reach financial independence, and, based on your savings, the age you'll get there. Results update as you type.
Your FIRE number is the portfolio that funds your spending indefinitely: annual spending ÷ withdrawal rate, which at a 4% rate is 25 times what you spend in a year. The page ships with $40,000 of retirement spending and a 4% withdrawal rate, so the target is $1,000,000. With $120,000 already invested, $1,000 a month going in, age 30, retirement at 65 and a 7% return against 3% inflation and 0% fees for a 4% real return, it projects you crossing that target at age 59 and finishing at about $1,373,446. Coast FIRE today would be $253,415. Change any assumption under Advanced assumptions. The rate traces to Bengen's 1994 paper and the Trinity Study; the method is documented in how our calculators work.
What is a FIRE number?
Your FIRE number is the size of investment portfolio that lets you cover your annual expenses from withdrawals indefinitely, the finish line of Financial Independence, Retire Early. The classic rule of thumb is the 4% rule: multiply your annual spending by 25 (that's the same as dividing by a 4% safe withdrawal rate).
How is your FIRE number calculated?
FIRE number = annual spending ÷ withdrawal rate (e.g. spending × 25 at 4%)
The calculator also projects your current investments plus monthly contributions forward in today's dollars, so you can see roughly what age you'll hit your number, and how much sooner a bigger contribution gets you there. If the target itself is new to you, the guide to the FIRE movement explains where it comes from.
FIRE numbers at common spending levels
Because the formula is just spending divided by withdrawal rate, you can sanity-check any target in your head. Here's what common annual budgets translate to at the standard 4% rate and the more conservative 3.5%:
| Annual spending | FIRE number at 4% | FIRE number at 3.5% |
|---|---|---|
| $30,000 | $750,000 | $857,000 |
| $40,000 | $1,000,000 | $1,143,000 |
| $60,000 | $1,500,000 | $1,714,000 |
| $80,000 | $2,000,000 | $2,286,000 |
| $100,000 | $2,500,000 | $2,857,000 |
Two things jump out. First, the relationship is linear: every extra $10,000 of annual spending adds $250,000 to your target at 4%. Trimming spending is therefore the most powerful lever you have, which is the entire logic behind Lean FIRE. Second, dropping from 4% to 3.5% raises every target by about a seventh, that's the price of extra safety.
Which withdrawal rate should you use?
The withdrawal rate is the assumption doing all the work, so pick it deliberately. 4% is the classic default and a reasonable planning figure for a retirement of around 30 years. 3.5% suits people retiring in their 30s or 40s who need the money to last 40 to 50 years, or anyone who wants margin against bad early-market luck. Some people go the other way and plan around 4.5% or 5% because they have flexible spending they can cut in a downturn, or income they expect later.
You don't have to marry one number. A sensible approach is to compute your target at both 4% and 3.5% and treat the space between them as your "working on it" zone: at the 4% figure you're arguably done, at the 3.5% figure you're done with a cushion. The 4% rule calculator lets you flip the question around and see what a given portfolio supports.
What counts as part of your portfolio?
Your FIRE number is compared against assets that can actually pay your bills, so be strict about what you count:
- Count: brokerage accounts, retirement accounts (401(k), IRA and equivalents), index funds, cash savings you intend to draw on. If it can be converted to spending money, it's in.
- Usually don't count: home equity. Your house doesn't pay you an income, and you still need somewhere to live. It only enters the math if you have a concrete plan to downsize and invest the difference.
- Pensions and Social Security: treat as spending offsets, not assets. A pension paying $10,000 a year from 65 doesn't add to your portfolio, it reduces the spending your portfolio must cover from that age, which at 4% cuts $250,000 off the target for those years.
Frequently asked questions
Is the 4% rule still reliable?
It comes from Bengen's 1994 paper and the Trinity Study that followed it, and held up across 30-year historical windows. For longer retirements or extra caution, many use 3.5%. Adjust the withdrawal rate under "Advanced assumptions" to see the impact.
Should I use today's spending or future spending?
Use the annual spending you expect in retirement, in today's dollars, the calculator handles inflation for you. Remember costs like a paid-off mortgage or Medicare can lower it.
What's the difference between my FIRE number and my Coast FIRE number?
Your FIRE number is the full target. Your Coast FIRE number is how much you'd need invested today for growth alone to reach that target by retirement, always a smaller figure.
Should taxes be part of my annual spending?
Yes. Withdrawals from pre-tax retirement accounts are taxable income, so the spending figure you divide by your withdrawal rate should include the taxes you'll owe on the way out. If most of your money is in Roth or taxable accounts with low gains, the tax drag is smaller, but budgeting something for taxes keeps the number honest.
Does Social Security lower my FIRE number?
Once it starts, yes, it acts like a spending offset. If you expect benefits to cover part of your spending later, subtract that amount from what your portfolio must fund from that age onward. Retiring very early means bridging many years before benefits begin, so most early retirees size their number without it and treat it as a safety margin, see the guides to retire at 40 and retire at 50 for how the bridge years change the math.
Is my FIRE number in today's dollars or future dollars?
Today's dollars. The calculator works in real, inflation-adjusted terms throughout, so the number it shows buys the same lifestyle whenever you reach it. That's why the return assumption is a real return, not a headline market return.
More FIRE calculators
Sources and further reading
The figures and rules on this page rest on the sources below, so you can check them rather than take our word for it.
- Bengen, W. P., Determining Withdrawal Rates Using Historical Data, Journal of Financial Planning, 1994 (FPA reprint, March 2004, member access), the origin of the 4% rule
- Cooley, Hubbard and Walz, Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable, AAII Journal, February 1998, the Trinity study
- How our calculators work, the formulas, defaults and tax year 2026 constants behind every figure on this site