TALLIVOInflation Calculator
What a sum of money was worth in any month from 1871 to 2026 — and what it would be worth in any other. Both directions, on the same CPI series the backtest uses.
Prices rose 332.78% over 46.5 years — an average of 3.20% a year.
$100 in Jan 1980 has the same buying power as $433 in Jul 2026 — prices rose 332.78% across those 46.5 years, which compounds to 3.20% a year. Turned around, $100 in cash held since 1980 now buys what $23 bought then.
Figures come from the Consumer Price Index, monthly, and cover a national basket of goods rather than any one household’s spending. Across the whole record from 1871 the average is 2.14% a year; measured only from 1913, where the official series starts, it is 3.17%.
The answer depends on when you start counting
Nearly every inflation calculator begins in 1913, because that is where the government’s official CPI-U series begins. That is a reasonable choice for a statistical agency and a misleading one for a reader, because it quietly excludes the only long stretch of American history in which prices went down and stayed down.
Between Jan 1871 and 1913, the price level fell 21.37%. Something that cost $100 in 1871 cost $79 four decades later. Include those years and long-run inflation is 2.14% a year; leave them out and it is 3.17%. Same country, same index, two different stories — and the shorter one is the one everybody quotes.
It produces a result that looks like an error and is not. Replacing $100 of 1913 spending today takes $3,436. Replacing $100 of 1871 spending — 42 years earlier — takes only $2,701. Older money is cheaper to replace, because the deflation between the two dates undid more than four decades of later inflation before it ever started.
This calculator runs on the CPI column of the Shiller dataset, which extends the official series back to 1871 using earlier scholarly price indices. Those pre-1913 figures are a reconstruction, not a government statistic. They are reliable for the shape of an era and not for arguing over a dollar, and the calculator flags any span that touches them.
The average is not the experience
2.14% a year sounds survivable. Nobody lives through an average. These are the worst sustained stretches in the record, each one the single worst window of its length:
| Over | Worst stretch | Per year | $100 became |
|---|---|---|---|
| 1 year | Jun 1919 → Jun 1920 | 23.67% | $124 |
| 5 years | Jun 1915 → Jun 1920 | 15.65% | $207 |
| 10 years | Jul 1972 → Jul 1982 | 8.81% | $233 |
| 20 years | Jan 1966 → Jan 1986 | 6.38% | $345 |
The worst single year in the whole series ends in Jun 1920 — the price spike that followed the First World War, when the index rose 23.67% in twelve months. The worst decade ends in Jul 1982, closing out the Great Inflation of the 1970s at 8.81% a year for ten straight years. A retirement plan built on the long-run average would have been wrong by a wide margin through both.
Two questions, two answers
“What is $100 from 1980 worth today?” is ambiguous, and the ambiguity is why people end up with numbers that seem to contradict each other. There are two questions:
- What does it cost now? To buy today what $100 bought in Jan 1980, you need $433. Prices went up, so this number is bigger.
- What does it still buy? $100 in cash, kept since Jan 1980, buys what $23 bought then — about 23% of its original power. Money sitting still loses, so this number is smaller.
Both are correct. They are reciprocals of the same ratio, and this calculator always shows you both so you never have to guess which one you are reading.
What $100 in each decade is worth in 2026
| $100 in | Costs today | Prices rose | Per year |
|---|---|---|---|
| 1880 * | $3,370 | 3270.37% | 2.43% |
| 1890 * | $4,423 | 4323.28% | 2.81% |
| 1900 * | $4,264 | 4163.64% | 3.01% |
| 1910 * | $3,403 | 3302.73% | 3.07% |
| 1920 | $1,745 | 1644.56% | 2.72% |
| 1930 | $1,969 | 1869.01% | 3.14% |
| 1940 | $2,422 | 2322.30% | 3.75% |
| 1950 | $1,433 | 1332.77% | 3.54% |
| 1960 | $1,149 | 1049.15% | 3.74% |
| 1970 | $891 | 790.74% | 3.95% |
| 1980 | $433 | 332.78% | 3.20% |
| 1990 | $264 | 164.29% | 2.70% |
| 2000 | $199 | 99.47% | 2.64% |
| 2010 | $155 | 55.39% | 2.71% |
| 2020 | $131 | 30.52% | 4.18% |
* Reconstructed price index rather than official CPI-U, which begins in 1913.
Why this matters for investing
A return you cannot spend is not a return. Over the whole record prices rose 27.0×, which is why the investment backtest reports real, inflation-adjusted returns by default rather than the larger nominal figure. It is also why the compound interest calculator, which projects nominal growth, will overstate what a balance can actually buy in thirty years’ time — the gap between those two numbers is exactly what this page measures.
Common questions
How much is $100 in 1980 worth today?
Why does this go back to 1871 when the government's calculator starts at 1913?
What is the average rate of inflation?
What was the worst inflation in US history?
Which direction does this calculator answer?
Does this include my own cost of living?
How we calculate this
One ratio does all the work: the CPI reading in the later month divided by the reading in the earlier one. Multiply by that ratio to get what a sum would cost later; divide by it to get what a sum still buys. The annual figure is that ratio compounded over the exact number of months between the two dates.
Nothing is modeled or assumed. Both readings come from the same committed monthly series the backtest runs on, so the number here and the inflation adjustment there can never disagree. Data as of Jul 2026.
Where to go next
This measures what money was worth. To run the other direction and project a balance forward with regular contributions, remember that the result is nominal — subtract inflation to see what it buys.
CPI measures a national basket, not your household. Pre-1913 figures are a scholarly reconstruction rather than an official statistic. Source: Robert J. Shiller, Online Data (shillerdata.com) — S&P Composite, dividends and CPI, monthly from 1871. Estimates for general information only — not financial, tax, or investment advice.