FIRE Calculator
Enter your income, spending, net worth, and expected investment return to find your FIRE number (the portfolio size that funds your retirement indefinitely), your current savings rate, and exactly how many years until you reach financial independence. The chart shows your projected net worth growing year by year to the FIRE target. Switch between FIRE variants - Lean, Standard, Fat, Coast, or Barista - to see how each strategy changes your timeline.
Formula
Worked example
An investor aged 30 with $50,000 saved, earning $80,000 and spending $48,000 per year, plans on $48,000/year in retirement. FIRE number = $48,000 / 0.04 = $1,200,000. Annual savings = $32,000. Real return = 7% - 3% = 4%. Years to FIRE = log((1,200,000 + 32,000/0.04)/(50,000 + 32,000/0.04)) / log(1.04) ≈ 18.4 years, retirement age ≈ 48.
What is FIRE and how does the 4% rule work?
FIRE (Financial Independence, Retire Early) is a movement built on one core idea: save and invest aggressively until your portfolio throws off enough passive income to cover your living expenses indefinitely - then stop working if you want to. The mathematical anchor is the "4% rule," derived from the 1998 Trinity Study by three finance professors at Trinity University. They back-tested a 4% annual withdrawal rate (adjusted each year for inflation) against every 30-year retirement window since 1926 and found that a diversified portfolio survived more than 95% of the time. Flipping the formula gives your FIRE number: annual retirement expenses divided by 0.04, which equals 25 times annual expenses. A household spending $50,000 a year needs $1.25 million invested before it can safely retire. The 4% rate is a starting point, not a law: many early retirees who face 40 or 50 year retirements use 3-3.5% to add safety margin, while those with flexible spending or part-time income can sometimes use 4.5-5%.
How your savings rate determines your retirement timeline
Savings rate is the most powerful lever in the FIRE equation - more powerful than investment returns, because you control it directly. A person saving 10% of income typically takes 40+ years to reach financial independence. At 25% savings, the timeline falls to about 32 years. At 50%, around 17 years. At 70%, under 9 years. The reason is mathematical: a high savings rate simultaneously shrinks the FIRE number (because you are spending less and therefore need a smaller portfolio) and increases the amount flowing into the portfolio each year. That double compression is why high-earners with moderate lifestyle inflation reach FIRE quickly, and why lifestyle creep is the main reason people miss their target dates. The savings rate this calculator uses is straightforward: (after-tax income minus annual spending) divided by after-tax income.
Lean, Standard, Fat, Coast, and Barista FIRE explained
The FIRE community has developed several variants to accommodate different lifestyles and risk tolerances. Lean FIRE targets very low annual spending - usually under $40,000 - and can be reached with $500,000 to $1,000,000. It demands a frugal lifestyle but can be achieved in 10-12 years on a median income with discipline. Fat FIRE is the opposite: maintaining a comfortable or even luxurious lifestyle, usually $100,000 or more per year, requiring $2.5 million or more. The timeline is longer but the retirement experience is higher-quality. Coast FIRE is a milestone rather than a finish line: you save aggressively until your portfolio is large enough that compound growth alone will carry it to your full FIRE number by traditional retirement age (typically 60-65), even if you contribute nothing more. Once you hit the Coast FIRE number, you can shift to a less demanding job or part-time work without sacrificing long-term financial security. Barista FIRE (named for the stereotype of working a coffee-shop job for health insurance) is a hybrid: you retire from your main career but take a part-time role whose income covers a portion of expenses, shrinking the portfolio you need to build. If part-time work covers $20,000 a year and your expenses are $50,000, you only need a portfolio to cover $30,000 - a FIRE number of $750,000 instead of $1.25 million.
What return rate and inflation assumptions are realistic?
Long-run real returns on a diversified US equity portfolio have averaged roughly 7% per year before inflation and about 4-5% after a 3% inflation adjustment. The default 7% nominal / 3% inflation in this calculator reflects a stock-heavy allocation such as 80-90% equities and 10-20% bonds - appropriate for someone two or more decades from retirement. As you approach FIRE, shifting toward bonds or cash reduces sequence-of-returns risk (bad early returns can permanently damage a portfolio) at the cost of lower expected growth. More conservative investors may prefer a 5-6% nominal return, translating to a 2-3% real return. International diversification, REITs, and other asset classes all affect your expected return. Use a number that matches your actual allocation rather than your aspiration, and consider running the calculator at two or three different return assumptions to see how sensitive your timeline is to that input.
FIRE variants at a glance
| Variant | Annual spend target | Typical FIRE number | Key trade-off |
|---|---|---|---|
| Lean FIRE | Under $40,000 | $500k - $1M | Minimal lifestyle, maximum speed |
| Standard FIRE | $40,000 - $80,000 | $1M - $2M | Balanced lifestyle and timeline |
| Fat FIRE | Over $100,000 | $2.5M+ | Comfort and flexibility, longer accumulation |
| Coast FIRE | Any | Depends on age | Contribute early, coast to retirement |
| Barista FIRE | $40,000 - $80,000 | $500k - $1M | Part-time work fills the gap |
Which flavour of FIRE suits your lifestyle? Each has a different spending level and strategy.
Frequently asked questions
What is the FIRE number and how is it calculated?
Your FIRE number is the total portfolio value you need to retire. The standard formula is: FIRE number = Annual retirement spending / Safe withdrawal rate. Using the 4% rule (SWR = 0.04) this equals 25 times your annual spending. For example, if you plan to spend $60,000 a year in retirement, your FIRE number is $1,500,000. The logic is that a 4% annual withdrawal from a diversified portfolio has historically survived all 30-year retirement periods tested.
Is the 4% rule still valid in 2026?
The 4% rule remains a widely cited benchmark, but many financial planners recommend a slightly lower rate - 3.3-3.5% - for retirements lasting 40-50 years, which is typical of someone retiring at 40 or 45. Some researchers argue that low bond yields in recent decades make the original Trinity Study assumptions less conservative than they appear. The safest approach is to use 3-3.5% if you expect a very long retirement, maintain some spending flexibility, or plan to reduce withdrawals during market downturns.
What is Coast FIRE and how do I know if I have reached it?
Coast FIRE is the point at which your invested assets are large enough that - even with zero future contributions - compound growth will carry them to your full FIRE number by a chosen traditional retirement age. The formula is: Coast FIRE number = FIRE number / (1 + real return)^(years until traditional retirement). If your current net worth is at or above that figure, you have "coasted" - you no longer need to save aggressively. You can downshift to a lower-paying job, work part-time, or simply spend all of your income while the portfolio grows on its own.
How does inflation affect my FIRE timeline?
Inflation erodes both purchasing power and effective investment returns. This calculator deducts your assumed inflation rate from the investment return to get the "real" return used in the growth formula. At 7% nominal return and 3% inflation, your real return is 4% - meaning your portfolio grows at 4% in terms of today's purchasing power. Inflation also means your FIRE number should be stated in today's dollars (as this calculator does), so the target automatically adjusts over time as prices rise.
Does the FIRE calculator account for Social Security or pension income?
Not automatically. The cleanest way to factor in Social Security, a pension, or rental income is to subtract those guaranteed income streams from your planned annual retirement spending before entering it in the "Annual spending in retirement" field. If you expect $20,000 a year from Social Security and plan to spend $60,000, enter $40,000 as your retirement spending. This reduces your FIRE number to $1,000,000 (at 4% SWR) rather than $1,500,000.
What is Barista FIRE?
Barista FIRE is a semi-retired strategy where you leave your high-income career but take a low-stress, part-time job to cover a portion of living expenses and possibly provide health insurance benefits. The "barista" name comes from the idea of working a coffee shop job. The key benefit is that even modest part-time earnings dramatically reduce the portfolio you need to accumulate: $20,000 a year in part-time income reduces your required FIRE number by $500,000 (at 4% SWR). Select the Barista FIRE option in this calculator and enter your expected part-time income to see how it reshapes your timeline.
Should I include my home equity in my FIRE number calculation?
Generally, no. FIRE calculators (including this one) focus on investable, liquid assets such as stocks, bonds, retirement accounts, and cash. Home equity is illiquid - you would need to sell the house to access it - and a primary residence does not produce income. However, if you plan to downsize and invest the proceeds, or move to a lower cost-of-living area at retirement, you could factor in the expected net proceeds from a home sale as a one-time addition to your investment portfolio.