FIRE Calculator

Enter current age, annual income, annual expenses, and current savings. Income and expenses determine the calculator’s savings rate and annual savings. Enter the expected annual return, withdrawal rate, and inflation assumption. The calculator also accepts income growth, expense growth, Social Security, a Social Security start age, and life expectancy.

Use annual figures on a consistent basis. If income is gross but expenses are after tax, the gap between them may overstate what you can invest. If you include taxes in expenses, make sure you do not subtract them twice. Likewise, include savings you actually intend to use for retirement rather than emergency cash or money set aside for near-term expenses.

The model caps some inputs to keep calculations within defined ranges: current age is limited to 18–100, annual return to −10%–30%, withdrawal rate to 0.5%–15%, Social Security start age to 62–70, and inflation, income growth, and expense growth to 0%–20%. Life expectancy must be after current age and is capped at 120. These are calculator bounds, not recommendations.

The savings rate is the share of income remaining after expenses. With the defaults, annual savings are $100,000 − $40,000 = $60,000. Dividing by income gives $60,000 ÷ $100,000 = 60%.

The FIRE number uses annual expenses divided by the withdrawal rate. The 4% rate is entered as 0.04 in the formula: $40,000 ÷ 0.04 = $1,000,000. The calculator’s current progress score is 15%, calculated as $150,000 ÷ $1,000,000 = 15%.

The projection estimates reaching the target in nine years, at age 39. It starts with $150,000, applies the assumed 7% annual return, and adds projected annual savings. Income grows at 3% per year and expenses at 2%, so the model’s annual savings change over time. The nine-year estimate is therefore not simply the result of dividing the $850,000 gap by $60,000.

The output also reports a longer projection point at age 45: savings of $2,353,454, comprising the initial $150,000 plus $1,210,117 in cumulative contributions and $993,337 in modeled investment growth. The chart stops five years after the projected FIRE year, which is why the displayed timeline extends through year 15 in this example.

Income, expenses, and savings rate

The savings rate shows the share of income not spent under the calculator’s income-minus-expenses approach. It is a useful measure of how strongly income and spending support wealth accumulation. It is not necessarily the percentage of take-home pay that reaches an investment account if the inputs use different tax bases.

Annual savings are floored at zero. If expenses exceed income, the model does not treat the gap as negative savings. It also does not separately model debt repayment or changes in savings vehicles.

Investment return and inflation

Annual return drives portfolio growth in the accumulation projection. A steady return is a simplification: real investment returns vary, and losses early in a plan can affect the timeline differently from losses later. The calculator’s return range allows assumptions as low as −10% and as high as 30%, but a permissible input is not a forecast.

Inflation and expense growth are separate inputs. Inflation is used in other projection elements, while expense growth directly increases modeled expenses each year. This distinction lets you test expense growth that differs from general inflation. If your spending rises faster than your assumptions, the FIRE target based on current expenses may understate your future need.

Withdrawal rate and FIRE number

The withdrawal rate converts annual spending into an asset target. A lower rate means a larger target and lower initial withdrawals as a share of assets. A higher rate reduces the target but can leave less room for poor market periods or a long retirement. A 4% rate is a planning heuristic, not a guaranteed safe rate for every retirement length or portfolio.

The FIRE number in this calculator is based on current annual expenses. It does not automatically rise each year with projected expense growth. The accumulation model grows income and expenses, but compares savings with the target calculated from the initial expense input. If your planned retirement expenses differ from current expenses, update the expense input or test the result with a separate spending-based target calculator.

Social Security and life expectancy

The calculator accepts Social Security as an optional future income source and uses the chosen start age in its retirement drawdown model. The default benefit is zero, so it does not reduce the default FIRE number. The calculator does not derive benefits from your earnings record. Use the SSA retirement estimator to obtain a benefit estimate and compare claiming ages.

Life expectancy sets part of the modeled retirement horizon. It is a planning assumption, not a prediction. A longer horizon can expose the plan to more years of inflation and market uncertainty. Explore how to retire early and the math behind FIRE before treating the timeline as a finish line.

Savings rate = (annual income − annual expenses) ÷ annual income

If income is zero or negative, the calculator reports a savings rate of zero. Annual savings are not allowed to fall below zero.

FIRE number = annual expenses ÷ withdrawal rate

For the default withdrawal rate, 4% becomes 0.04 in the calculation.

Annual savings in each projected year =
maximum of (projected income − projected expenses) or zero

Income and expenses grow using their respective annual growth assumptions. The portfolio grows by the annual return, then adds that year’s savings.

Next year’s savings balance =
current balance × (1 + annual return) + annual savings

The sequence applies a simplified, constant return and annual contribution model. It does not simulate market volatility, investment fees, taxes, or account-specific contribution rules. It also does not adjust the FIRE number dynamically as expenses grow during accumulation.

A higher savings rate can shorten the accumulation period through two channels: it increases the amount invested and often reflects a lower spending level that could reduce the retirement target. The calculator’s scenario curve illustrates timelines at different savings rates. In the provided results, the 20% savings-rate scenario reaches its target in 25 years, while the 80% scenario reaches its target in 4 years.

Those curve values show modeled outcomes under the calculator’s assumptions; they are not promises. The 80% savings rate may require a very different income and expense pattern from the defaults. Also, lowering expenses can change the target itself. To compare spending styles, explore Lean FIRE and Fat FIRE, or look at Barista FIRE if you plan to continue earning some income.

The 40% row is a scenario prompt, not a pre-computed calculator output. Use the calculator’s curve to read the result for your exact assumptions.

The default $1,000,000 target comes from $40,000 of annual spending divided by 4%. At 3%, the same spending would require $40,000 ÷ 0.03 = about $1,333,333. At 5%, it would require $40,000 ÷ 0.05 = $800,000. The lower target at 5% comes with a higher initial withdrawal rate, which leaves less margin if returns are weak or retirement lasts longer than expected.

The calculator’s default output says the portfolio may last to age 106 under its drawdown assumptions, or 67 years after the modeled FIRE point at age 39. Treat that as a result of a simplified sequence, not a reliability guarantee. A fixed average return cannot reproduce the damage that a market decline can cause when withdrawals continue.

The U.S. Department of Labor explains that investment choices and diversification affect retirement-plan risk in its retirement savings guidance. The SEC’s investor education resources provide information about risk and investing. For retirement account withdrawal rules, the IRS explains required minimum distributions; account access rules can matter when retiring well before age 59½.

A FIRE target is only one part of early-retirement readiness. You also need a plan for health insurance, account access, taxes, and income before Social Security. Different strategies address these needs in different ways:

• Coast FIRE focuses on whether existing savings may grow toward a later goal without additional contributions. Explore the Coast FIRE Calculator.
• Barista FIRE assumes some paid work continues, potentially reducing the amount withdrawn from savings.
• Sabbatical FIRE examines a temporary break from work rather than permanent retirement; use the Sabbatical FIRE Calculator.
• FIRE with real estate or side income models income sources beyond a conventional investment portfolio; compare FIRE with Real Estate and FIRE with Side Income.

These approaches can reduce portfolio withdrawals, but they introduce different uncertainties. Rental income can involve vacancy and repairs; part-time employment can change; and a side business may not provide steady cash flow. Model income conservatively and avoid counting the same source both as a reduction in expenses and as portfolio income.

The score of 15% is the current balance divided by the target. It is a progress indicator, not a grade or a probability of success. The nine-year estimate is sensitive to the assumed return, future savings, income growth, and expense growth. A one-year delay or a large unexpected expense can change the timeline.

The chart separates contributions from investment growth. In the displayed age-45 projection, cumulative contributions are $1,210,117 and modeled growth is $993,337. Investment growth is a projection, not a guaranteed share of the eventual balance. The calculator assumes the annual return can be applied consistently, while actual portfolios experience both positive and negative years.

The model also does not ask whether your savings are in taxable, tax-deferred, or Roth accounts. Those balances can have different tax consequences and withdrawal rules. A useful next step is to assess how money would be accessed at different ages, using a Retirement Withdrawal Calculator and a Retirement Withdrawal Strategy Calculator.

1. Check your spending baseline. Use at least 12 months of spending and include irregular costs.
2. Use a conservative return scenario. Compare the default with a lower return and note the change in target timing.
3. Test withdrawal rates. Compare the 4% default with lower rates, particularly for an early retirement that may last decades.
4. Separate accumulation from retirement. Include healthcare, taxes, and the years before Social Security or other benefits begin.
5. Review account access. Identify which assets can be used at each age and any tax or penalty consequences.
6. Update regularly. Recalculate when salary, expenses, family needs, or investment assumptions change.

For a broader starting point, read what the FIRE movement is and compare the Retirement Number Calculator. These help frame the target, but a detailed spending and withdrawal plan is still necessary.

What is a FIRE number?

A FIRE number is an estimated portfolio target based on annual spending and a selected withdrawal rate. In this calculator, annual expenses are divided by the withdrawal rate.

Does the calculator include Social Security in the default FIRE number?

No. The default Social Security benefit is zero. If you enter a benefit, the calculator uses its start age in the retirement income projection, but the basic FIRE number is still calculated from annual expenses and the withdrawal-rate input.

Does 4% guarantee that my savings will last?

No. A 4% withdrawal assumption is not a guarantee. It does not eliminate market, inflation, longevity, tax, or spending risk.

Why is the target based on current expenses if my expenses grow?

The calculator calculates the FIRE number from the initial annual expense input. Expense growth affects the accumulation projection, but the target itself is not recalculated each year. If future retirement spending will be different, change the expense assumption and test separate scenarios.

Should I count home equity as savings?

Count it only if you plan to make it available for spending, such as by downsizing or selling. Otherwise, adding it may overstate assets available to fund expenses.

Should I save more or reduce expenses to reach FIRE sooner?

Either can help, but the effect differs. Saving more accelerates accumulation; lower spending can also reduce the asset target. Test each separately and choose a plan you can maintain.

Does a 60% savings rate mean I invest 60% of take-home pay?

Not necessarily. The calculator divides the difference between entered annual income and expenses by income. If income is gross and expenses are after tax, the result may not equal your actual investment rate.

Why does the projection show a portfolio lasting to age 106?

That is a simplified model outcome under its return and withdrawal assumptions. It does not represent a statistical probability or guarantee that a real portfolio will last to that age.

Does the calculator include taxes, fees, or health insurance?

No. Add realistic spending for these items to annual expenses, and remember that taxes can depend on which accounts fund withdrawals. Health insurance costs can also change before Medicare eligibility.

What if my income or expenses change more than the assumptions allow?

The calculator limits several inputs to specified ranges, including income and expense growth of 0%–20%. If your situation requires assumptions outside those limits, run a separate scenario or use a year-by-year budget model.

Treat the estimated FIRE age as a scenario to challenge. Confirm the spending target, test lower returns and withdrawal rates, and plan how you will cover taxes, healthcare, and the bridge to future benefits. Then compare a conventional portfolio plan with options such as Coast or Barista FIRE. Run the calculator again as your circumstances change; a useful FIRE plan is one you can adjust, not just a target you calculate once.