FIRE Calculator

What Is the FIRE Calculator?

The FIRE Calculator helps you work out how much money you need to achieve Financial Independence and Retire Early, and how many years it will take to get there at your current savings rate. Enter your expected annual retirement expenses, current portfolio value, annual investment contribution, expected return rate, and safe withdrawal rate to get your full FIRE number, years and projected year to reach it, Coast FIRE milestone, and a comparison of Lean, Regular, and Fat FIRE targets. The calculator solves for time to FIRE by iterating compound portfolio growth year by year until the projected portfolio reaches your target, so the timeline accounts for the compounding effect of returns on both your existing portfolio and ongoing contributions working together.

Financial independence as a structured goal gained mainstream attention after the publication of early retirement blogs and the 2012 release of work-optional frameworks that gave a generation of savers a concrete mathematical target. Given that the underlying formula is simple division, the harder part is almost always getting the inputs right: what you will actually spend in retirement, what return rate is realistic for your portfolio, and whether 4% is the right withdrawal rate for your specific retirement horizon. This calculator surfaces all three variables so you can figure out how sensitive your FIRE timeline is to each one. Once you have a FIRE number in mind, our Net Worth Calculator helps you track how your total assets and liabilities line up against that target as a percentage of your overall financial picture.

The 4% Rule and How to Calculate Your FIRE Number

Your FIRE number equals your expected annual retirement expenses divided by your safe withdrawal rate. At the standard 4% rate, this works out to 25 times your annual spending. A household planning to spend $80,000 per year in retirement needs a portfolio of $2,000,000 to sustain that level of withdrawals indefinitely under the historical returns the original research modelled. The 4% figure comes from the 1994 Trinity Study, which analysed 30-year retirement periods across historical US market data and found that a balanced stock and bond portfolio could support 4% annual withdrawals adjusted for inflation with a very high success rate across most historical market conditions.

For early retirees with a horizon longer than 30 years, many practitioners recommend pulling that rate down to 3% or 3.5%, since the original research was not designed for 40 to 50-year retirements. The table below shows how the withdrawal rate changes your required portfolio size at the same $70,000 annual spending target.

On top of that, your withdrawal rate choice has a larger impact on your FIRE number than almost any other variable. Moving from 4% to 3.5% adds $250,000 to the required portfolio at $70,000 annual spending. That said, it also buys significantly more resilience against poor early-retirement market returns, a risk known as sequence of returns risk that is most severe in the first decade of retirement. With that in mind, choosing the withdrawal rate is a risk tolerance decision as much as a math decision.

FIRE Types: Lean, Regular, Fat, Coast, and Barista

Lean FIRE targets a minimal lifestyle, typically below $40,000 per year, and requires a smaller portfolio but demands permanent frugality. Regular FIRE aims to replicate your current lifestyle in retirement. Fat FIRE adds a meaningful spending buffer, usually 1.5 times your current expenses or more, to cover healthcare costs, travel, and lifestyle upgrades without financial stress. The calculator shows all three targets simultaneously so you can narrow down which version fits your actual life rather than a generic assumption.

Coast FIRE is a milestone rather than a retirement type. You have reached Coast FIRE when your current portfolio is large enough to grow to your full FIRE number by age 65 with no further contributions, purely through compound returns. Once you hit this point, you only need to earn enough to cover current living expenses, since the portfolio handles the rest. Many people find this milestone more motivating than the full FIRE number because it is often reachable a decade earlier. Barista FIRE sits between Coast and full FIRE: you stop full-time work but take part-time employment to cover living costs while the portfolio grows. The IRS 401(k) contribution limits are worth knowing regardless of which FIRE type you are pursuing, since maxing out tax-advantaged accounts is one of the most efficient ways to build up your portfolio during the accumulation phase.

Accuracy and Limitations

This calculator uses a constant annual return rate for portfolio growth and a fixed withdrawal rate, both of which are simplifications of real market behaviour. In practice, returns vary significantly year to year, and a sequence of poor returns in the early years of retirement can deplete a portfolio even if long-run averages recover, a risk the static model cannot capture. The calculator also does not adjust for inflation during the accumulation phase, which means the real purchasing power of your FIRE number at a future date will be lower than the nominal figure shown if inflation runs above your expected return. As a result, treat the timeline as an estimate rather than a guarantee, and build in a buffer of 10 to 20% above your calculated FIRE number as a practical margin of safety.

The model does not include Social Security benefits, pension income, rental income, or part-time earnings that could reduce how much you need to withdraw from the portfolio. If you carry out a more detailed retirement income projection using your Social Security Administration retirement estimator, you can subtract your expected annual benefit from your spending target before entering it into this calculator, which will reduce your FIRE number meaningfully, particularly if you have a long employment history before retiring.

The Most Common FIRE Planning Mistake

The most consistent FIRE planning error I encounter is people using their current take-home pay as a proxy for retirement spending rather than actually budgeting what retirement will cost. Current income includes savings contributions, commuting costs, work clothing, meals out during work days, and payroll taxes that disappear in retirement. On the other hand, it often excludes healthcare, since many people receive employer-subsidised coverage and have never paid the full market rate, and it underestimates leisure spending because retired life has more hours to fill. Given that healthcare costs for a couple in their early 50s can run $15,000 to $25,000 per year on the private market, and that retirement travel and leisure often increase spending compared to working years, the real-world retirement budget is frequently higher than the current after-tax income would suggest. I have seen people calculate a $1.2 million FIRE number from their current spending only to realise after building a proper retirement budget that the real figure is closer to $1.7 million. Use our Budget Calculator to build a detailed retirement spending model first, then bring that annual total into this calculator to get a FIRE number that reflects your life, not a generic assumption.