FIRE stands for Financial Independence, Retire Early — the idea that you can stop relying on a paycheck once your investment portfolio is large enough to fund your living expenses forever. This FIRE calculator from Smekys does two jobs at once. First, it sizes your FIRE number — the nest egg you need — using the classic 4% safe withdrawal rate. Second, it projects how many years it will actually take you to get there, given what you already have saved, how much you add each year, and the return your money earns.
Type in your numbers and the result card updates instantly. You will see your target nest egg, the monthly income it can spin off, how far you are today, and the estimated year you cross the finish line.
How to Use
- Enter your Annual Spending in Retirement. Use what you actually plan to spend, not what you earn. A household that lives on $60,000 a year needs a very different nest egg than one that lives on $120,000.
- Set the Safe Withdrawal Rate. The default 4.0% comes from the Trinity Study and is the most widely cited benchmark. Slide it down toward 3.5% if you want a more conservative plan, or up toward 4.5% if you are comfortable with more sequence-of-returns risk.
- Type your Current Savings & Investments — everything already earmarked for retirement, including 401(k), IRA, and taxable brokerage balances.
- Enter the Amount You Save Each Year directly in dollars. If you are not sure, take your monthly investment and multiply by 12. Entering dollars (rather than a percentage of income) keeps the math transparent.
- Set your Expected Annual Return. A diversified stock-and-bond portfolio has historically averaged roughly 7% nominal per year. If you want an inflation-adjusted view, try 5%–6% real.
The engine then compares your growing balance against your target. If you have already passed it, the calculator tells you that you are financially independent today.
The 4% Rule and Your FIRE Number
The FIRE number comes straight from the Trinity Study (Cooley, Hubbard, and Walz, 1998), which tested 30-year payout periods on historical market data. The rule of thumb that emerged: a portfolio that you draw down at an initial 4% per year has a very high chance of lasting 30 years or more.
That flips neatly into a simple target:
Target Nest Egg = Annual Spending ÷ (Withdrawal Rate)
At the 4.0% benchmark, dividing by 0.04 is the same as multiplying your annual spending by 25. If you spend $50,000 a year, your FIRE number is $50,000 × 25 = $1,250,000. Draw 4% of that in your first year — $50,000, or about $4,167 a month — and adjust subsequent withdrawals for inflation.
The multiplier moves with the withdrawal rate. A 3.5% rate implies roughly 28.6 times spending; a 4.5% rate implies about 22.2 times. Choosing 3.5% instead of 4.5% raises your target by nearly 30%, which is why the withdrawal-rate slider is worth stress-testing.
How the Years-to-FIRE Math Works
Knowing the target is only half the battle. The harder question is when you get there. Smekys models your balance as a lump sum that compounds plus an annuity of annual contributions:
Balance(n) = Current × (1 + r)^n + Annual Savings × ((1 + r)^n − 1) / r
Setting that equal to your target and solving for n gives the years-to-FIRE:
n = ln( (Target + Annual Savings/r) / (Current + Annual Savings/r) ) / ln(1 + r)
Where r is your expected annual return as a decimal. If the expected return is 0%, the formula gracefully falls back to a simple straight-line gap: years = (Target − Current) ÷ Annual Savings. If your current savings already exceed the target, n is 0 — you have arrived.
Examples
Example 1 — The classic $50k lifestyle. A couple plans to spend $50,000 a year. At a 4.0% withdrawal rate their FIRE number is $1,250,000. They already have $400,000 invested and add $40,000 each year, earning 7%. The calculator projects they reach the target in roughly 9–10 years, after contributing about $360,000 of fresh savings on top of their existing balance.
Example 2 — Starting from scratch. The same $1,250,000 target, but starting from $0 while saving $40,000 a year at 7%: the annuity alone needs about 17–18 years to compound to the target. This shows why a high starting balance shortens the runway so dramatically — compounding on a large lump sum does most of the heavy lifting.
Example 3 — A six-figure spender. Someone who wants to spend $200,000 a year needs a $5,000,000 nest egg at the 4% rule. With $2,000,000 already invested and $100,000 added yearly at 7%, the calculator reports about a 9-year runway. Slide the withdrawal rate to 3.5%, however, and the target jumps to ~$5.7M — adding several years and illustrating how sensitive the plan is to that single assumption.
FAQ
What is the FIRE number and how is it calculated?
Your FIRE number is the investment balance you need so that withdrawals, rather than a paycheck, cover your spending. It equals your annual spending divided by your safe withdrawal rate. At the 4% benchmark that is annual spending times 25 — spend $50,000 and you need $1.25 million.
Is the 4% rule still safe?
The 4% rule comes from the Trinity Study, which looked at U.S. markets over several decades. It holds up well for a balanced portfolio over 30-year horizons, but it is not a guarantee. Many planners now use 3.5% to build in margin, especially for early retirees who may be funding 50 or more years of withdrawals.
How much do I need to save each year to retire early?
Enter your target nest egg, your current balance, and an expected return; the calculator solves for the years it takes at your chosen annual savings. To find the reverse — the annual savings needed by a certain date — raise or lower the savings slider until the years-to-FIRE matches your goal.
Does this calculator account for inflation?
The default 7% expected return is a nominal figure and the spending is in today's dollars. For a more conservative, inflation-adjusted estimate, enter a 5%–6% real return and leave spending in today's dollars; the resulting target already reflects the 4% rule's inflation-adjusted withdrawal logic.
What is the difference between FIRE and normal retirement?
Normal retirement typically begins around age 65–67 after a working career. FIRE means reaching your financial independence number early — often in your 30s, 40s, or 50s — by saving a very high share of income and letting compounding do the rest. The math is identical; only the target age differs.
Should I count my home equity in the nest egg?
Usually no. A home is illiquid and you still need somewhere to live in retirement. Keep home equity out of the investable nest egg unless you plan to downsize or rent it out for actual spendable cash. Retirement accounts, brokerage, and cash are the inputs that belong here.
Disclaimer
This FIRE calculator is provided for informational purposes only and does not constitute financial, investment, tax, or legal advice. All figures are estimates based on the inputs you enter and the 4% safe-withdrawal model; future returns, inflation, and personal spending can differ substantially from your assumptions. Investment involves risk, including the possible loss of principal. Always consult a qualified financial advisor before making retirement decisions.