A FIRE calculator: your FIRE number, and Lean, Fat, Coast and Barista FIRE
FIRE — financial independence, retire early — means investing enough that the portfolio can pay your living costs for good. This FIRE number calculator turns your expected yearly spending into a target, using a safe withdrawal rate you choose (4% by default), and works out how many years your savings take to get there.
It shows every flavour side by side: Lean FIRE on a bare-bones budget, regular FIRE, Fat FIRE with room for extras, Coast FIRE — the amount that, left alone, grows to your target by a normal retirement age — and Barista FIRE, where part-time income covers some of the bills. Everything is in today’s money with inflation built in, so it works as a FIRE calculator with inflation for India in rupees as well as in dollars, pounds or euros.
How to use the FIRE Calculator (Lean, Fat, Coast & Barista)
- Choose the currency (rupees load Indian example figures), your age, what you have invested now and what you invest each year.
- Enter yearly spending in retirement for Lean FIRE, your plan and Fat FIRE, in today’s money.
- Set the withdrawal rate, the expected return and inflation. Add take-home income to see your savings rate.
- Open “Coast and Barista FIRE” to set the age you could coast to and your part-time income.
- Read your FIRE number, the years to reach it, and the table of every target; copy the summary.
FIRE Calculator (Lean, Fat, Coast & Barista) features
FIRE number
Yearly spending ÷ withdrawal rate: 25× spending at 4%, about 28.6× at 3.5%.
Years to FI
Year-by-year growth at the real (after-inflation) return, with your savings rising with prices.
Lean and Fat FIRE
Two more spending levels you set yourself, with their own targets and dates.
Coast and Barista FIRE
What you need now to stop saving, and the smaller target when part-time work pays part of the bills.
Rupees, dollars, pounds
Indian lakh/crore formatting and Indian example figures when you pick rupees.
How the FIRE numbers are worked out
FIRE number = yearly spending ÷ withdrawal rate. Spending $40,000 at 4% needs $1,000,000. Coast FIRE = FIRE number ÷ (1 + real return)years to the coast age: at a 7% real return and 30 years, $1,000,000 needs only $131,367 today. Barista FIRE = (spending − part-time income) ÷ withdrawal rate.
Years to FI: each year the portfolio grows by the real return, (1 + return) ÷ (1 + inflation) − 1, and your yearly investment is added. Investing $100,000 a year at a zero real return reaches $1,000,000 in exactly 10 years. The savings rate (investing ÷ take-home pay) is the strongest lever: the more you save, the less you spend and the smaller the target.
Where the 4% rule comes from, and its limits
- William Bengen (1994) tested withdrawals against US market history from 1926: 4% of the starting balance, raised each year with inflation, lasted at least 30 years in every period he studied. The 1998 Trinity study reached a similar answer.
- Early retirees may need money for 40–50 years, so many use 3–3.5%. In India, with higher inflation and a shorter market history, 3–3.5% (a 28–33× multiple) is common.
- The result ignores taxes, fees beyond your net return, and sequence-of-returns risk — a crash just after you stop working hurts most.
- Health costs before government pensions or Medicare start are a common gap in FIRE plans.
Next steps
Plan conventional retirement with the retirement calculator, US tax-advantaged saving with the 401(k) calculator and Roth IRA calculator, and Indian monthly investing with the SIP calculator. To test drawing down a corpus, try the SWP calculator.
FIRE Calculator (Lean, Fat, Coast & Barista) FAQ
What is a FIRE number?
The amount you need invested so that withdrawals at your chosen rate cover your yearly spending. At 4% it is 25 times what you spend in a year.
What is Coast FIRE?
Having enough invested that, without adding anything more, it grows to your FIRE number by a traditional retirement age. After that you only need to earn your living costs.
What are Lean FIRE and Fat FIRE?
Lean FIRE targets a frugal budget; Fat FIRE a comfortable one with travel and extras. The calculator shows both alongside your planned spending.
What is Barista FIRE?
Leaving full-time work once your portfolio covers the spending that part-time income does not. Part-time pay of $20,000 cuts a $40,000-a-year target from $1,000,000 to $500,000 at 4%.
How do I use this FIRE calculator in India?
Choose rupees, enter yearly expenses in today’s money, and use a return and inflation that suit Indian markets — the Indian example uses 11% and 6%. Consider a 3–3.5% withdrawal rate.
Can couples use the FIRE calculator?
Yes. Enter combined household spending, investments and yearly savings; the targets are for the household.