How the Conversion Works
Equivalent amount = amount × (CPI in target year ÷ CPI in start year). The CPI-U measures the average price change of a representative basket of goods and services for urban consumers — about 93% of the US population. If the index doubled between your two years, you need twice as many dollars to buy the same basket.
Two caveats worth knowing. First, the CPI is an average basket: healthcare, rent, and education have outpaced the index for decades, while electronics and clothing lag it — your personal inflation rate depends on what you actually buy. Second, annual averages smooth over within-year swings; the January-to-January numbers you hear in the news differ slightly.
A Century of Inflation in One Sentence
The dollar has lost roughly 97% of its purchasing power since 1913 — what $1 bought then takes about $32 now. Set the calculator to 1913 → 2025 to see it live.
At the long-run average of about 3% per year, prices double every ~23 years. That's the quiet force that makes "keep cash under the mattress" a losing strategy over a working lifetime — and why the rule of thumb says long-term savings belong in assets that grow faster than inflation.
The Three Big Inflation Episodes
- 1917–1920 (WWI): Peaked near 18% in 1918 as war finance flooded the economy with money, then reversed hard into the 1921 deflation.
- 1974–1982 (the Great Inflation): Oil shocks plus loose policy pushed inflation to 13.5% in 1980. It took the Volcker Fed's double-digit interest rates and two recessions to break it — the episode that defined a generation's view of inflation.
- 2021–2022 (post-pandemic): Supply chains, stimulus, and energy shock produced 8% annual inflation in 2022 — the highest in 40 years, and the first time younger households experienced it firsthand. By 2024–2025 it had settled back to the 2.5–3% range.
The Rare Years Prices Fell
General deflation is rare: since 1913, annual averages fell year-over-year only in 1921, 1922, 1926, 1928–1934 (the Depression), 1938, 1949, and 1955. Select those years above and the "Total Inflation" panel goes negative — try 1929 → 1933, when prices collapsed about 25% in four years, a fall that made Depression-era debts heavier even as wages fell alongside.
Data: US Bureau of Labor Statistics, CPI-U annual averages (bls.gov/cpi).
Common Questions
Which data does this calculator use?
Official US Bureau of Labor Statistics data: CPI-U annual averages for all items, US city average, base 1982-84=100, covering 1913 through 2025. Annual averages smooth out month-to-month swings, which makes them the right series for converting purchasing power between years.
Why do some year pairs show negative inflation?
Because prices actually fell in those periods — deflation. Since 1913, annual averages dropped year-over-year in 1921–1922, 1926, 1928–1934 (the Great Depression), 1938, 1949, and 1955. Try 1929 → 1933: prices fell about 25% in four years, which is why Depression-era debts became crushing even as prices fell.
Is this the same inflation rate I hear in the news?
Close, but not identical. News headlines usually report the year-over-year change in a single month's index, seasonally adjusted. This calculator uses annual averages — the average of all 12 months — which smooths those monthly wobbles. Over multi-year spans the two methods converge; the long-run average since 1913 is about 3.2% per year either way.
Related Calculators
- Compound Interest Calculator — Growth that outruns inflation
- Retirement Calculator — Savings goals in future dollars
- Salary Calculator — Whether a raise beat inflation