FIRE Calculator

Your FIRE number is the size of the invested portfolio that lets you live off withdrawals indefinitely. It equals your expected annual retirement expenses divided by your safe withdrawal rate: FIRE number = annual expenses / (SWR/100). At the classic 4% rate that simplifies to annual expenses × 25, so spending of 40,000 a year implies a 1,000,000 target.

The 4% rule says you can withdraw 4% of your starting portfolio in the first year of retirement, then adjust that amount for inflation each year, with a high chance the money lasts about 30 years. It comes from the 1998 Trinity Study (Cooley, Hubbard & Walz), which found a stock-heavy portfolio survived roughly 95% of historical 30-year windows at a 4% inflation-adjusted withdrawal. The 25× multiple is simply 1 divided by 0.04.

25 is the mathematical inverse of 4%: 1 / 0.04 = 25. Withdrawing 4% of a pot each year is the same as needing 25 years of expenses saved. A 3.5% rate maps to about 28.6×, a 3% rate to 33.3×, and a 5% rate to 20× — lower withdrawal rates are safer but require a bigger corpus.

Take your realistic annual spending in retirement and multiply by 25 (for a 4% withdrawal rate) or by 100/SWR for any other rate. For example, 60,000 of annual spending needs 1,500,000 at 4%, or about 1,714,000 at 3.5%. This calculator also projects how many years your current savings plus monthly investments will take to reach that target.

It is debated. The 4% rule was tested on a 30-year horizon, but early retirees may need their money to last 40-50+ years and face sequence-of-returns risk in the first decade. Critics such as Wade Pfau and Early Retirement Now suggest 3.25-3.5% is safer for long horizons, while William Bengen and Michael Kitces argue 4% is actually conservative. Because the safe withdrawal rate is an input here, you can model whichever assumption you trust — lowering it raises your target corpus.

They are lifestyle variations of the same math. Lean FIRE means a frugal retirement on a modest budget (and a smaller FIRE number). Fat FIRE funds a higher-spending, more comfortable lifestyle (a larger number). Coast FIRE means you have saved enough early that compounding alone reaches your number by your target age, so you only need to cover current expenses. Barista FIRE means you cover most costs from your portfolio and top up with flexible part-time work. Each one changes the annual-expenses input, not the formula.

Coast FIRE is the point where your existing investments, left untouched, will grow to your full FIRE number by your planned retirement age — without any further contributions. After hitting Coast FIRE you only need to earn enough to cover today's living costs. To model it, set your monthly investment to 0 and check whether your current savings alone reach the target by the age you want.

We project your portfolio month by month: each month the balance earns the monthly return (annual return / 12) and your monthly contribution is added at the end of the month. The number of months until the balance first reaches or exceeds your FIRE number, divided by 12, is your years to FIRE. With 50,000 saved, 1,500 invested monthly and a 7% return, a 1,000,000 target is reached in about 243 months, or 20.25 years.

This calculator treats the return you enter as nominal, so the FIRE number is in today's nominal currency. If you want results in today's purchasing power, enter a real return instead — for example, use 4% rather than a 7% nominal return when you expect about 3% inflation. Be consistent: a real return pairs with expenses in today's money.

Yes. The math is currency-agnostic — FIRE number = annual expenses / safe withdrawal rate works in rupees, dollars, euros or any currency. Indian FIRE planners face higher inflation (CPI 6-7% vs the US 2-3% used in the Trinity Study) and often lower equity allocations in retirement, so many use a more conservative 2.5-3.5% withdrawal rate instead of 4%. At 3%, the corpus multiple rises to 33x rather than 25x — a roughly 32% larger target. Healthcare inflation in India runs at 10-14% a year, compounding faster than lifestyle expenses, so building a separate medical buffer or shaving another 0.5% off your withdrawal rate is common practice. Set your own return and SWR to match your market and horizon.

Your savings rate is the most powerful lever in the FIRE equation — more so than investment returns over short-to-medium horizons. It works a double shift: a higher savings rate means you invest more each year (faster accumulation) AND that your required FIRE number is smaller (lower spending). Assuming a 5% real return, 4% SWR and starting from zero: saving 20% of take-home pay takes about 37 years; 30% takes 28 years; 40% takes 22 years; 50% takes 17 years; 60% takes 12 years; 70% takes about 9 years. Every 10 percentage points added to your savings rate at the higher end saves roughly 3-5 years; at the lower end the gains are even larger. Use this calculator with different monthly investment figures to see the effect directly.

Sequence-of-returns risk is the danger that a run of poor market returns in the early years of retirement — before your portfolio has had time to recover — depletes the corpus faster than average long-run returns would suggest. If markets fall 40% in year 2 of retirement, you are forced to sell units cheaply to fund living costs; those units can never participate in the recovery. A person who retired in 2000 (just before the dot-com crash) faced a far worse outcome than one who retired in 2003, even with identical 20-year average returns. This is why many FIRE practitioners choose a SWR of 3-3.5% rather than 4%: the lower rate builds a cushion against bad early sequences. This calculator shows the deterministic path; for sequence risk modelling, pair it with a Monte Carlo simulator.

It is a deterministic estimate: it assumes a constant average return with no market crashes or volatility, and it ignores taxes on withdrawals, healthcare costs, one-off expenses, and spending that changes over a long retirement. Real outcomes are a range, not a single path, so treat the result as a planning guide and consider a Monte Carlo tool and a financial professional before acting.

No. It is an educational projection based on the assumptions you enter, not personalised financial advice. Investment returns, inflation, taxes and your own spending will differ from any single estimate. Use it to understand the trade-offs between saving more, spending less and choosing a withdrawal rate, and consult a qualified adviser before making retirement decisions.