Data1975–2024, 50 years
StocksS&P 500 total return
Non-stock10-yr Treasury total return
RunsIn your browser
What this calculator actually does
FIREcalc runs a savings calculator and a retirement calculator in your browser. Nothing you type is sent to a server to compute the result.
The data, 1975–2024
- Stocks: S&P 500 total return, including dividends. 1975–2020 is the series this app already used. 2021–2024 had been price returns (dividends left out) and are now total returns: 28.47%, −18.04%, 26.06%, and 24.88%, from Damodaran’s S&P 500 series.
- Non-stock sleeve: that year’s 10-year US Treasury total return, from Aswath Damodaran, NYU Stern, “Historical Returns on Stocks, Bonds and Bills” (January 2026). This is not the Bloomberg US Aggregate. Treasury returns can be negative. 2022 was −17.83% in the same year stocks were −18.04%. The series is more volatile than a total-bond-market fund.
- Inflation: the CPI rate already stored on each row, paired with that year’s stock return.
The table starts in 1975. It does not include 1966 or 1973–74, which are among the hardest US retirement start dates. A success rate here is not a full-history Trinity or Bengen study.
Two ways to use the table
- Shuffled years: each simulated year is drawn at random from the 50 rows. Stock return, Treasury return, and inflation stay together for that draw. The next year is independent. The simulation count is how many of these paths run. This is not a historical sequence.
- Historical cycles: the model walks forward through the years that actually followed a start year. Retirement keeps only complete windows. A 30-year retirement has 21 windows (1975–2004 through 1995–2024). A 50-year retirement has one window. Savings uses every start year from 1975 until the goal or until 2024, so a start near the end of the sample has only a few years of data.
Shuffled paths use a fixed random seed until you press Reshuffle. The same inputs give the same result, so when the result moves, it moved because of what you changed. A share link carries the seed.
Savings goal is today’s purchasing power
The dollar goal you type is what you want in today’s dollars. Each year the portfolio earns that year’s stock and Treasury return, income and spending rise with that year’s inflation, and the contribution is income minus spending (never below zero). The model compares portfolio ÷ cumulative inflation to your goal. Charts and milestones are in today’s dollars. A nominal balance can pass the goal number while purchasing power has not.
Retirement success
Success means the portfolio is still above zero at the end of every year of the horizon you chose. The year’s return is applied before the withdrawal. If “Raise spending with inflation” is on, spending rises with inflation starting in the second year. The first year uses the spending amount you typed. Simple taxes gross spending up by 1 ÷ (1 − tax rate). There is no fee, no glide path, and no separate cash bucket.
Social Security is off unless you open “Social Security & other income” and turn it on. When it is on, the result says the monthly benefit, the claiming age, and that the income is inside the success rate. That rate is then not a portfolio-only withdrawal test. The default used to leave a $2,000 monthly benefit checked behind a collapsed panel. It no longer does.
What the headline numbers are
- Savings shows the median number of years to the real goal. Beside it are the 10th percentile (the faster 10% of paths got there by then) and the 90th percentile (the slower 10% took at least that long), and the share of paths that reached the goal within 50 years.
- The retirement range chart shows, at each age, the 10th, 25th, 50th, 75th, and 90th percentile of balance across all paths. A path that ran out counts as $0 from then on. The median line is the middle balance at each age, not one path.
- The retirement range chart starts in today’s dollars (each path’s balance divided by its own cumulative inflation), with a switch to future dollars. Summary figures and the path table show future dollars, with today’s dollars beside them where labeled. Savings charts are in today’s dollars.
- “What moves the date” and “What moves the odds” rerun up to the first 1,000 of the same paths for each point, changing one input at a time.
FAQ
What is FIRE?
FIRE means financial independence, retire early: save and invest enough that work becomes optional. A common starting point is a portfolio of about 25 times annual spending, which is a 4% initial withdrawal. That is a rule of thumb, not a result this tool prints by itself.
What is the 4% rule, and does this tool reproduce it?
The published 4% rule (Bengen, and the Trinity study) measured an inflation-adjusted withdrawal over historical retirement cohorts, using historical stock and bond returns. This tool can run a similar question only in Historical cycles mode, and only inside 1975–2024. Shuffled years are a different statistic. A 15% tax makes a $40,000 after-tax withdrawal a larger pre-tax draw. Social Security, if you turn it on, lowers the portfolio withdrawal and raises the success rate. Read the note under the result before treating the percentage as a 4% test. The “Classic 4% check” starting point sets Historical cycles, 50% stocks, a 0% tax rate, inflation-adjusted spending, and Social Security off.
How do I know if I’ve reached my FIRE number?
Type the portfolio you want in today’s purchasing power. The savings calculator reports how many years the median path takes to get there after inflation. Reaching a nominal balance equal to that number is not the same thing.
How accurate are these projections?
They replay or reshuffle one 50-year US large-cap and Treasury sample. They leave out fees, returns before 1975, and markets outside this table. Use them as a planning sketch. For a decision about when to retire, compare Historical cycles with Shuffled years, and with Social Security off, before trusting a high success rate.
Which result should I plan on?
The savings screen shows the median with the 10th and 90th percentile beside it. Plan closer to the slower number, not the median. Use Historical cycles as the sequence check and Shuffled years as a wider stress test. A single median is a weak plan if the retirement is long.
How do I read the “When you might get there” chart?
Each bar is how many paths reached the real goal in that year. The line is the running total of paths that had reached it by then. Paths that never reach the goal are omitted from the bars. In historical mode, some of those misses are short windows at the end of the sample.
What does retirement success rate mean?
It is the share of paths that still had money at the end of every year of your horizon. In historical mode the denominator is the number of complete windows, which is small. 21 windows of 30 years is not the same as a century of overlapping cohorts.
How are taxes handled?
Simple mode applies one rate: pre-tax need = spending ÷ (1 − rate). Detailed mode uses 2025 federal brackets, the standard deduction, and long-term gains on half of taxable-account withdrawals. Brackets are not inflation-indexed while withdrawals grow, so long retirements drift into higher brackets. Social Security taxability uses married-filing-jointly thresholds even if you select single. The “optimize withdrawal order” box does not change the result, because account balances are not tracked. Withdrawals stay split by the percentages you enter. The model does not include early-withdrawal penalties, RMDs, NIIT, IRMAA, or ACA premiums.
How do I include part-time work, a pension, or Social Security?
Open “Social Security & other income” and enter them there. Do not also subtract that income from the withdrawal, or you will count it twice. Social Security uses the benefit at full retirement age (67) and scales it for the claiming age you pick. It receives a cost-of-living adjustment. A pension stays flat in nominal dollars.
How is inflation handled?
Savings: the goal stays in today’s dollars and the balance is deflated. Retirement: turn on “Raise spending with inflation” if spending should hold its purchasing power. The first retirement year uses the amount you typed. Later years use the inflation rates from the path.
What does the stock slider mean?
The stock share earns the S&P 500 total return. The rest earns the 10-year Treasury return for the same year, including years when Treasuries lose money. There is no separate cash yield and no glide path.
What does a share link contain?
Share link copies your inputs, and the random seed, into the page address. Anyone with the link sees those numbers. The link also sits in browser history and in ordinary hosting logs. See the privacy policy.