“How much do I need to retire?” is the first question in personal finance. The age variants — at 40, at 50, at 55, at 60, at 65 — are what the search engines suggest when you type it in, and this site’s own data for September 2026 recorded them as the most recurring question of the niche.
The answers on offer are a survey number or a slogan: a million, two million, seventy percent of your salary.
The question is a number in disguise, and the arithmetic can be shown step by step. It starts from spending, not from savings. It uses dated 2026 inputs. It ends with a multiple.
The Question as It’s Asked
The age variants carry two different questions, and they get two different answers.
One: “I am 40 — or 50, or 55, or 60. What number do I need to reach, and how many years will it take?” That is a gap question: the distance between the number and now, and the years to close it at the contribution rate that actually exists.
The other: “I want to retire at 40, or 50, or 55 — not 65. What does that do to the number?” That is a horizon question: the same spending, a longer payout, a lower sustainable rate.
Both answers start from the same multiple, and the multiple comes from a dated test.
The 25x Rule, and the Study It Comes From
You want to spend X dollars a year in retirement, in today’s dollars. The portfolio has to pay X every year and still be alive at the end. The most-cited retirement rate in planning — 4%, the first-year withdrawal, indexed for inflation, across thirty years — is what the dated record says a portfolio can sustain.
The arithmetic, step by step:
- Portfolio times 4 percent equals first-year spending.
- Solve for the portfolio: first-year spending divided by 0.04.
- That is 25 times first-year spending. The 25x rule is the 4% rule read backward.
The 25x is not an invented number. It is the reciprocal of a tested rate, and the rate has a date. William Bengen ran the test in the October 1994 issue of the Journal of Financial Planning: thirty-year withdrawal periods against U.S. market data back to 1926, and 4% was the highest first-year rate that never exhausted a portfolio in any window of that data. Cooley, Hubbard, and Walz at Trinity University backtested the same idea in the February 1998 issue of the AAII Journal, against data back to 1925, and found high success rates at 3–4% for stock-dominated portfolios.
That is the whole pedigree: a 1994 test, a 1998 confirmation, both with dates. Turn the rate around and the question “how much do I need to save” becomes “how much do I spend.” That is the frame the listicles skip: the number is built from the life you want to afford, not from a savings target.
The assumption behind the number is dated too. The thirty-year horizon, the 4% rate, the inflation indexing — each is an input with a date, and each can be re-dated. The number is only as good as the assumption behind it.
The 2026 Number: Spending to Portfolio
Here is the table in 2026 dollars. The dated 2026 inputs are named: inflation of 3.4% over the twelve months through August 2026, core 2.4%, per the Bureau of Labor Statistics; the 10-year U.S. Treasury at 5.01% on September 16, 2026, and the Federal Reserve at a 3.75–4.0% range, the dated rate set recorded on this site; the 4% rule with its 1994/1998 pedigree.
The center column is the 25x at 4%. The right columns are the edges, shown with their dates: the worst thirty-year window in the 1926–2014 rolling data sustained only 3.5%, and a horizon longer than thirty years — retiring before 65 — points to rates near 3% in the dated studies. The full data is in the 4% rule, stress-tested, published on this site in September 2026. That article rounds the edges — “about 29x” and “33x”; the exact multiples are 28.6x and 33.3x, and they are in the table.
| Spending you want, per year (2026 dollars) | At 4% — 25x | At 3.5% — 28.6x, worst window 1926–2014 | At 3% — 33.3x, horizon over 30 years |
|---|---|---|---|
| $40,000 | $1,000,000 | $1,142,857 | $1,333,333 |
| $50,000 | $1,250,000 | $1,428,571 | $1,666,667 |
| $60,000 | $1,500,000 | $1,714,286 | $2,000,000 |
| $70,000 | $1,750,000 | $2,000,000 | $2,333,333 |
| $80,000 | $2,000,000 | $2,285,714 | $2,666,667 |
Read the table as a frame, not a price list. The $60,000 row is a life, not a sum — food, housing, health, the rest, in 2026 dollars. Inflation is running at 3.4% headline and 2.4% core. The dollars in the table will cost more in 2027, and that is why the plan indexes the withdrawal and why the number is stated in the year’s dollars.
The life table says the horizon is the assumption to watch. The 2024 U.S. life table, published by the National Center for Health Statistics in August 2026, puts life expectancy at birth at 79.0 — a record, above the 78.9 of 2014 — and a person who reaches 65 as 19.7 more years, to 84.7. Forty-four percent of Americans, 43.8% by the table, live past 85. A thirty-year plan at 65 covers to 95. The number has to be built for the years the table actually holds. That is why the 3% edge is in the table at all.
Social Security sits under the number, not inside it. The full retirement age has been raised from 65 to 67, per the 2026 Trustees Report. The spending figure the table uses is what the benefit does not cover.
The Gap: Age to Years to Close
Now the question as the reader asks it, by age. The base case is stated, because the number is only as good as the assumption behind it: the number is $1.5M — $60,000 of spending at 25x. Current savings are $0, the worst case. Growth is 0%, the slowest path. The only inputs left are age and the dated 2026 contribution limits: $24,500 a year in a 401(k) or 403(b), plus $8,000 of catch-up at 50, plus the $11,250 super catch-up for ages 60–63. Those are the IRS figures for 2026.
| Age now | Years to 65 | What the 2026 limits put in by 65 | What is still missing at 65 | Years to close the rest, at $32,500 a year | The number is reached at |
|---|---|---|---|---|---|
| 40 | 25 | $745,500 | $754,500 | 23.2 | about 88 |
| 50 | 15 | $500,500 | $999,500 | 30.8 | about 96 |
| 55 | 10 | $338,000 | $1,162,000 | 35.8 | about 101 |
| 60 | 5 | $175,500 | $1,324,500 | 40.8 | about 106 |
| 65 | 0 | $0 | $1,500,000 | 46.2 | about 111 |
Read the last two columns together. The older you start, the older you are when the number is reached — at zero growth, the dated limits alone do not close the gap to a $60,000 life at 65. That is not a verdict on you. It is the arithmetic of the slowest path, with no assumption doing the work.
In the benefits office, the number someone was handed and the number that survived were rarely the same animal. This table is the same move on the saving side: the number you were handed, and the number the dated inputs actually produce.
The Worked Example: Age 50, $200,000, Dated Rates
The zero-growth table is the floor. Run it at the dated rates and read the gap. The same 50-year-old, but with $200,000 saved, contributing the 2026 maximum of $32,500 a year for fifteen years — and growth at two dated rates: 6% real, the after-inflation long-run record of the U.S. equity market since 1926 that this site uses, and 3% real, a stated planning assumption for the lower end of the range.
At 6% real:
- $200,000 grows to $479,310.
- Fifteen contributions of $32,500 grow to $756,470.
- Total at 65: $1,235,780 — 82% of the $1.5M number.
- The remaining $264,220, at $32,500 a year and 6% growth, closes in 6.8 more years. The number is reached at about 72.
At 3% real:
- $200,000 grows to $311,594.
- Fifteen contributions grow to $604,470.
- Total at 65: $916,064 — 61% of the number.
- The remaining $583,936 closes in 14.6 more years at 3%. The number is reached at about 80.
Run it at the lower rate and the higher rate and read the gap: eight years between the two, and it came entirely from the assumption, not from the contribution. Same limit, same discipline, different rate. Change one input and re-run it — the number moves with the rate.
Where the Number Comes From, and How to Update It
The whole number is four inputs, each with a date:
- The rate: 4%, from the 1994 test and the 1998 confirmation. The edges are 3.5% for the worst window in the 1926–2014 data, and 3% for a horizon over thirty years.
- The inflation: 3.4% headline, 2.4% core, the twelve months through August 2026, per the Bureau of Labor Statistics. The table is in 2026 dollars because of it.
- The limit: $24,500, plus $8,000 at 50, plus $11,250 for ages 60–63 — the IRS figures for 2026.
- The life: 79.0 at birth, 19.7 years past 65, 43.8% past 85 — the 2024 U.S. life table, published August 2026.
Each input re-dates on its own schedule: the inflation every month, the limit every January, the life table every year, the rate whenever the data is re-run. That is how the number stays a number, dated, rather than a slogan.
The mechanics of the re-run, with every formula and input exposed, are in the retirement calculator. Whether the number you get survives its first decade — the order of the years, the sequence of returns — is the 4% rule, stress-tested.
The number, dated.