FIRE Number Estimator
Financial independence is a number. This tool helps you find yours — and shows you what most calculators leave out.
How to read this
The FIRE number. Your FIRE number is the portfolio size at which a fixed annual withdrawal rate covers your living expenses without drawing the principal down to zero. The widely cited 4% rule comes from the Trinity Study, which back-tested 30-year retirement horizons against historical market data and found that withdrawing 4% of the starting balance, adjusted annually for inflation, had a very high probability of lasting the full 30 years. Early retirees face a longer horizon — often 50+ years — which is why 3.5% is the more honest default for someone retiring well before traditional retirement age. The smaller the percentage, the larger the portfolio needed, but the more durable it is.
Coast FIRE. Coast FIRE is the point at which your existing portfolio, if left alone with no new contributions, will compound to your full FIRE number by your target retirement age. Reaching Coast FIRE does not mean you can stop working — you still need income to cover living expenses. It means you no longer need to save aggressively for retirement. The visual of the coast phase, where the line keeps rising after you stop contributing, is the most motivating output in this tool because it shows compounding doing the work on its own.
The sequence of returns risk. During the accumulation phase, the order of investment returns barely matters — only the long-run average does. In the withdrawal phase, the order matters enormously. If markets fall in your first years of retirement, you sell shares at depressed prices to cover spending, leaving fewer shares to recover when prices eventually rise. The same average return delivered in a different order can leave one retiree comfortable for 40 years and another out of money in 20. We default to the unfavorable scenario because the honest plan accounts for bad luck, not just average luck.
Why the adjusted number is higher. A Traditional 401k balance looks impressive on a statement, but the IRS owns a slice of it — every withdrawal is taxed as ordinary income. A Roth balance, by contrast, is yours free and clear. A taxable brokerage account sits in the middle, owing long-term capital gains on the growth portion at withdrawal. The adjusted FIRE number grosses up the Traditional and taxable portions of your portfolio so the after-tax balance matches your real spending need. For most people with meaningful pre-tax balances, the honest number is meaningfully higher than the simple one.
About the default values
Annual spending in retirement defaults to $40,000. That is close to the median individual spending level for a US adult once housing, transportation, food, healthcare, and discretionary categories are summed. It is a deliberately modest figure — meant to represent a comfortable but not lavish lifestyle. Replace it with your own number to get a personally meaningful FIRE target.
Withdrawal rate defaults to Conservative at 3.5%. This is more conservative than the widely cited 4% rule because the Trinity Study's 4% finding assumed a 30-year retirement horizon. Early retirees often face 40 to 60 year horizons, and the math degrades quickly as the horizon lengthens. The 3.5% default reflects this honest reality.
Your current age defaults to 26. This is the age at which most professionals have settled into their first real career role and are facing meaningful financial decisions for the first time. It is also the age at which Ethan and Cody begin their story in The Two Paths Saga.
Target retirement age defaults to 55 because the entire point of the FIRE conversation is early retirement — the year where the math of leaving traditional employment first becomes plausible for most disciplined savers. Adjust it up or down to model your own timeline.
Current portfolio value defaults to $100,000. This reflects a meaningful savings milestone rather than a starting-from-zero assumption — the level at which someone has been saving for several years and is now thinking seriously about the path to financial independence. Set it to your actual invested balance for a personalized projection.
Monthly savings defaults to $1,000. This reflects someone who has made a deliberate decision to prioritize financial independence — roughly 20% of a median individual income. The national personal savings rate is much lower; this default is intentionally aspirational because the math rewards it significantly.
Annual savings increase defaults to 3.0%. US wages have historically grown at approximately 3% annually, roughly in line with inflation. This default models your contributions growing modestly each year as your income grows.
Expected annual return defaults to 7.0% when After inflation is selected and 10.0% when Before inflation is selected. The S&P 500 has historically delivered approximately 10% nominal and 7% real annual returns since 1926. This is not a guarantee but it is the most historically defensible long-term assumption available.
Portfolio tax treatment defaults to 60% Traditional, 30% Roth, 10% taxable brokerage. This roughly reflects the typical mix for a US professional who has been contributing primarily to an employer-sponsored 401k while also funding a Roth IRA, with a small taxable account for shorter-horizon goals.
Estimated tax rate at withdrawal defaults to Higher than today. US tax rates are historically low by long-run standards, federal deficits are persistent, and the honest planning default is to assume rates rise from here. You can switch to Similar or Lower if you have a specific reason to expect otherwise.
Monthly healthcare cost before Medicare defaults to $800. The average ACA marketplace premium for an unsubsidized individual is approximately $800 per month, with significant variation by state, age, and plan selection. This input only appears when your target retirement age is below 65 — the year of Medicare eligibility.
Sequence of returns defaults to Unfavorable. This is the most important honest default in the entire tool. The order of returns matters enormously in the withdrawal phase, and retiring into a down market is the primary reason FIRE plans fail even when the long-term math looked right. The unfavorable default is chosen because honest financial planning accounts for adverse scenarios, not just average ones.
Default values last reviewed: January 2026. Investment return assumptions use a 3% long-run inflation assumption consistent across all Charted Course tools.