FIRE Calculator

What is FIRE?

FIRE stands for financial independence, retire early. A FIRE calculator estimates the amount you may need invested to support your yearly spending, along with how long your current savings plan could take to reach that amount. It is a financial independence calculator for planning, not a promise about when you can stop working.

The calculator estimates your FIRE number by dividing yearly spending by your safe withdrawal rate. It then projects savings growth using your current investments, yearly savings and real return, which is the return after inflation. A Coast FIRE calculator also estimates how much you would need invested today for growth alone to reach your FIRE number by your traditional retirement age.

Why your FIRE number matters

A target can help you connect everyday spending and saving decisions to a longer-term plan. If your estimated timeline feels too long, you can compare the effect of spending less, saving more or changing your assumptions before making major choices about work or retirement.

Your yearly spending has a direct effect on the FIRE number. Lower ongoing costs can reduce the amount you need to fund. Your savings rate and investment growth affect the estimated timeline. That can help you assess trade-offs such as increasing a retirement contribution, delaying a large purchase or deciding whether a change in work hours fits your plan.

Coast FIRE is a different milestone. It estimates whether your current investments could grow to your FIRE number by traditional retirement age without additional contributions. The estimate depends on the return you enter and the age you select. This is a planning tool, not individualized investment or tax advice; consider reviewing retirement assumptions with a qualified financial or tax professional.

How to use this FIRE calculator

1. Enter your current age and yearly spending. Use your actual spending as a starting point, and consider whether your expected retirement spending would differ. Include costs you expect to keep paying, such as housing, food, transportation and health care.
2. Enter a safe withdrawal rate. This is the rate used to calculate the FIRE number from yearly spending. The calculator uses the rate as an assumption; it does not determine which rate is right for your circumstances.
3. Add the amount you have invested so far and how much you expect to save each year. Use amounts you can reasonably support in your budget, rather than a contribution level you may not sustain.
4. Enter your expected real return after inflation. This assumption affects both the projected years to FIRE and the Coast FIRE estimate. Investment returns vary, so try different assumptions to understand how sensitive the result is.
5. Enter the traditional retirement age you want to use for the Coast FIRE estimate. Then review the FIRE number, years to FIRE, estimated age when you reach it, Coast FIRE number today and whether the result says you are already coasting.

FIRE calculator example

How to read your FIRE calculator results

Your FIRE number is the target produced by your yearly spending and withdrawal-rate inputs. It is not a guaranteed amount that will cover every future expense. If your spending estimate leaves out costs you expect in retirement, the target may be too low. If it includes costs you will no longer have, it may be too high.

Years to FIRE and the estimated age are projections based on the savings and real return you entered. They assume those inputs continue as entered. The calculator does not know whether your income, expenses or investment returns will change, and the result does not account for every possible tax or investment cost. Treat the timeline as an estimate, not a date you can rely on.

How to improve your FIRE plan

1. 01

   Check your spending estimate

   Review your recent spending and identify costs that are recurring, optional or likely to change in retirement. Consider how a lower ongoing expense would change your FIRE number before deciding to cut something from your budget.

2. 02

   Set a savings amount you can maintain

   Look for a contribution increase that fits your cash flow. For example, consider raising your 401(k) contribution by one point if your budget can support it. Revisit the calculator after a pay increase or a change in regular expenses.

3. 03

   Test assumptions instead of relying on one forecast

   Run the calculator with different spending, savings and real-return assumptions. Compare how the timeline changes, and avoid treating an optimistic return as certain. Ask a qualified professional to help you assess retirement and tax considerations.

Common FIRE calculator mistakes

• Using current spending without checking retirement costs

  Your current budget may not match what you expect to spend after leaving work. Review housing, health care, travel and other major costs rather than assuming today's total will carry over unchanged.

• Treating the safe withdrawal rate as a guarantee

  The rate is an input to the calculation, not a promise that your savings will last for a particular period. Try different assumptions and get qualified guidance before making a retirement decision.

• Reading the projection as a fixed schedule

  The timeline depends on the values you enter. A change in savings, spending or real returns can change the estimate. Update the inputs when your circumstances change.

The FIRE formula

Key terms

FIRE number

The estimated amount needed to support yearly spending, calculated by dividing yearly spending by the safe withdrawal rate.

Safe withdrawal rate

The rate entered into the calculator to estimate the FIRE number from yearly spending.

Real return

Investment return after inflation, used to project the growth of savings in purchasing-power terms.

Coast FIRE

A point at which investments already saved could, through growth alone, reach the FIRE number by the traditional retirement age entered.