Inflation Calculator — Real BLS CPI Data 1913–2024
What was $100 in 1970 worth today? Use 112 years of real BLS Consumer Price Index data to answer. Three modes: historical CPI-based lookup, forward flat-rate projection, and backward flat-rate adjustment.
| Year | CPI-U | Equivalent | YoY |
|---|
What Is Inflation?
Inflation is the rate at which the general level of prices rises, reducing the purchasing power of money. A candy bar that cost 5¢ in 1960 costs about 75¢ in 2024 — not because the candy bar became 15× more valuable, but because the dollar lost purchasing power. Economists measure inflation by tracking the price of a standardized basket of goods and services over time.
In the United States, the canonical measure is the Consumer Price Index for All Urban Consumers (CPI-U), published monthly by the Bureau of Labor Statistics. CPI-U tracks roughly 80,000 prices collected from retail stores, service providers, and rental landlords across 75 urban areas, weighted by how much a typical urban household spends on each category.
Because CPI uses a fixed base year (1982-84 = 100), any two CPI values can be compared as a ratio. If 1970 CPI is 38.8 and 2024 CPI is 313.689, the ratio 313.689 / 38.8 = 8.08 tells you that it takes about $8.08 today to buy what $1 bought in 1970.
The Formula
Amount— the starting dollar amount in the original year.CPIstart— annual average CPI-U for the starting year (from BLS).CPIend— annual average CPI-U for the end year.
This is the CPI-based method and gives the most accurate historical answer. For forward projection beyond 2024 (or any scenario where you prefer a flat annual rate instead of real data), use the compound formula:
r— assumed annual inflation rate (typically 2–3% for the US).n— number of years.
Worked Example — What Was $100 in 1970 Worth Today?
38.8.313.689.313.689 / 38.8 = 8.0848. Every 1970 dollar equals about $8.08 today.$100 × 8.0848 = $808.48.Cumulative inflation: 708.5%. Average annual rate: ~3.92%.
US Inflation by Decade — Annual Averages
Inflation is rarely steady. The table below shows the average annual CPI-U inflation rate for each decade since 1920, computed from the full BLS dataset:
| Decade | Average annual inflation | Notable events |
|---|---|---|
| 1920s | -0.9% | Post-WWI deflation; mild price declines |
| 1930s | -2.0% | Great Depression deflation 1930–33 |
| 1940s | 5.4% | WWII price controls, post-war 1946 jump (+18%) |
| 1950s | 2.1% | Korean War, stable growth |
| 1960s | 2.5% | Vietnam War spending begins |
| 1970s | 7.4% | Oil shocks, Great Inflation, stagflation |
| 1980s | 5.1% | Volcker disinflation after 1980 peak of 13.5% |
| 1990s | 3.0% | Moderation; Fed credibility restored |
| 2000s | 2.6% | Housing bubble and 2008–09 deflation scare |
| 2010s | 1.8% | Post-GFC subdued inflation, mostly below Fed target |
| 2020–2024 | 4.3% | COVID supply shocks, 2022 peak of 9.1% YoY |
Source: TopFinClub calculation from BLS CPI-U annual averages. Decade rates are geometric means of the embedded annual-change data.
Types of Inflation
Creeping inflation (1–3% per year)
A small, steady rise in prices. Most central banks, including the Federal Reserve, target inflation in this range because a small positive cushion discourages deflation and lubricates labor-market adjustments. The Fed's official target is 2% PCE inflation.
Walking or moderate inflation (3–10%)
High enough to erode savings noticeably and prompt behavioral change. The US experienced persistent walking inflation for most of the 1970s. Households begin shifting toward real assets (real estate, equities, commodities).
Galloping inflation (10%+ per year)
Severely disruptive. Businesses struggle to plan; long-term contracts break down. The US briefly flirted with this in 1974 (11.0%) and 1979–81 (peak 13.5%). Many emerging-market economies have lived through galloping inflation for years at a time.
Hyperinflation (50%+ per month)
Catastrophic collapse of a currency's purchasing power. Classic cases: Weimar Germany 1921–23, Hungary 1946 (highest recorded in history), Zimbabwe 2008, Venezuela 2016–19. US data has never recorded hyperinflation.
Deflation (negative inflation)
A sustained decline in general prices. Sounds good for consumers, but a deflationary spiral is feared because debt burdens rise, wages become sticky-downward, and people postpone purchases. The US saw severe deflation in 1930–33 (-10.3% in 1932 alone) and a brief dip in 2009 (-0.4%).
Disinflation
A slowdown in the rate of inflation (e.g., from 6% to 3%) — not the same as deflation. The Volcker Fed engineered disinflation in the early 1980s; the 2023–24 environment was disinflationary as CPI fell from 8% back toward 3%.
What Causes Inflation?
Economists identify three primary mechanisms, plus a monetary framing:
- Demand-pull inflation — aggregate demand grows faster than productive capacity. "Too much money chasing too few goods." Happens when the economy is at full employment and consumers, governments, or investors spend more.
- Cost-push inflation — input costs rise (wages, commodities, energy, imports) and producers pass the costs to consumers. The 1973 oil shock is the textbook example.
- Built-in inflation — workers expect rising prices and bake them into wage demands, which firms pass into prices, creating a self-reinforcing wage-price spiral. Cost-of-living-adjustment clauses in contracts amplify this effect.
MV = PY (money supply × velocity = price level × real output). In this view, sustained inflation is always rooted in money growth outpacing real output.How to Beat Inflation
Historically, the best inflation hedges for long-term savers have been:
- TIPS (Treasury Inflation-Protected Securities) — US Treasury bonds whose principal adjusts with CPI. The real yield is locked in; inflation risk is transferred to the government. Ideal for fixed-income portions of a portfolio.
- I Bonds — US savings bonds combining a fixed rate and a CPI-linked rate, reset twice a year. Capped at $10,000 per person per year via TreasuryDirect. Best used for emergency-fund-adjacent savings.
- Broad stock-market index funds — S&P 500 total return has outpaced inflation by roughly 7% per year on average over the last century. Equities are volatile short-term but are the strongest long-horizon inflation hedge.
- Real estate — residential and commercial property tends to track or exceed inflation over multi-decade periods, and rental income generally rises with CPI.
- Commodities and gold — often cited as inflation hedges; work best in acute supply-shock inflations (1970s), less reliable in demand-driven inflations.
Rule of 72 — How Fast Prices Double
Divide 72 by the annual inflation rate to estimate how many years it takes for prices to double:
- At 2% inflation → prices double in 36 years
- At 3% inflation → prices double in 24 years
- At 5% inflation → prices double in 14.4 years
- At 7% inflation → prices double in 10.3 years
- At 10% inflation → prices double in 7.2 years
This is the inflation analogue of the Rule of 72 for investment growth. It's a quick mental shortcut — the exact value is log(2)/log(1+r).
How to Use This Calculator
- Pick a mode. CPI mode uses real BLS data for historical years (1913–2024). Forward Projection applies a flat future rate. Backward Adjustment reverse-adjusts future dollars to past purchasing power.
- Enter an amount. Use the sliders, type in directly, or pick a quick preset ($100 / $1K / $10K / $100K / $1M).
- Pick start and end years. In CPI mode, both years must be between 1913 and 2024 — our last complete BLS annual average. In the flat-rate modes, any year range works, and you can also set an annual rate below.
- Read the result — today's equivalent, cumulative inflation, and average annual rate are shown in the top-right panel.
- Copy the share link to send your exact query to someone else — the URL preserves your inputs and mode.
Methodology & Assumptions
- CPI mode uses BLS CPI-U annual averages (series CUUR0000SA0, not seasonally adjusted, base 1982-84 = 100). Calculation:
amount × (CPI_end / CPI_start). - Forward Projection mode compounds forward at a user-entered flat rate:
amount × (1 + r)^n. Useful for modeling future scenarios where real CPI does not yet exist. - Backward Adjustment mode discounts future dollars back to an earlier year's purchasing power at a flat rate.
- Full dataset is embedded in-page and downloadable as CSV. Backing JSON at
/calculators/data/cpi-annual.json. - No network calls, no tracking, no server. All math runs in your browser and you can verify it in DevTools.
Glossary
- CPI (Consumer Price Index)
- A measure of the average change over time in prices paid by urban consumers for a market basket of goods and services, published monthly by the Bureau of Labor Statistics.
- CPI-U
- The CPI for All Urban Consumers — the broad headline series (CUUR0000SA0) covering roughly 93% of the US population. This is the series the calculator uses.
- Core CPI
- CPI excluding food and energy, which are volatile. Used to see underlying trends; often referenced by the Federal Reserve for policy decisions.
- PCE (Personal Consumption Expenditures) price index
- An alternative inflation measure published by the Bureau of Economic Analysis; it re-weights based on current spending. The Fed's formal 2% inflation target uses PCE, not CPI.
- Real vs nominal
- Nominal amounts are in the currency of the day (the number on a price tag or paycheck). Real amounts are adjusted for inflation, so different years can be compared apples-to-apples.
- Hyperinflation
- Extremely high and accelerating inflation, generally defined as 50% or more per month. US data has never recorded hyperinflation.
- Deflation
- A sustained decline in the general price level. Historically associated with severe recessions.
- Disinflation
- A slowdown in the rate of inflation (e.g., from 6% to 3%). Not the same as deflation, which is negative inflation.
- Stagflation
- Simultaneous high inflation and high unemployment with slow growth. The 1970s US economy is the textbook case.
- TIPS
- Treasury Inflation-Protected Securities. US Treasury bonds whose principal adjusts with CPI, providing a guaranteed real return.
- Purchasing power
- The quantity of goods or services a fixed amount of money can buy. Inflation erodes purchasing power; deflation increases it.
Frequently Asked Questions
Using BLS CPI-U annual averages, $100 in 1970 has the same buying power as about $808 in 2024. The CPI rose from 38.8 in 1970 to 313.689 in 2024 — cumulative inflation of approximately 708%, an average of roughly 3.92% per year.
Use this formula: adjusted = amount × (CPI_today / CPI_past). For example, $100 × (313.689 / 38.8) = $808. The CPI ratio tells you how many of today's dollars equal one dollar from the past year. Cumulative inflation in percent = (CPI_today / CPI_past − 1) × 100.
CPI (Consumer Price Index) is published by the Bureau of Labor Statistics and measures the average price change for a fixed basket of goods and services. PCE (Personal Consumption Expenditures) is published by the Bureau of Economic Analysis and weighs categories by actual spending, which changes as people substitute. The Federal Reserve formally targets 2% PCE inflation; media more often cites CPI. PCE typically runs about 0.3 percentage points below CPI.
Between 1913 and 2024, CPI-U rose from 9.9 to 313.689. That is cumulative inflation of about 3,068%, or an average annual compound rate of ~3.18%. Inflation varies sharply by decade: the 1970s averaged 7.4% per year, the 2010s about 1.8%.
Economists recognize three main causes: demand-pull (demand exceeds supply), cost-push (rising production costs passed to consumers), and built-in (wage-price spirals baked into contracts). Monetarists add a fourth: growth in the money supply outpacing real output, per Milton Friedman's MV=PY identity.
Historically effective hedges include TIPS (CPI-indexed Treasuries), I Bonds, broad stock index funds (equities have outpaced inflation by ~7% annually over the last century), real estate, and commodities as partial hedges. The worst option is holding excess cash in a zero-interest account — at 3% inflation, cash loses roughly 26% of its real value over ten years.
Since CPI tracking began in 1913, the highest annual rate was 18.1% in 1946 (post-WWII price control lifting). Modern peaks include 13.5% in 1980, 11.0% in 1974, and a 9.1% year-over-year print in June 2022. The 1921 depression saw −10.8% deflation, the largest single-year decline. Germany's 1923 Weimar hyperinflation was not a US event.
Deflation — sustained falling prices — is usually bad. When people expect prices to keep falling, they delay spending; demand drops; firms cut production and lay off workers; existing debt burdens rise because nominal debts stay fixed while wages fall. The Great Depression (1929–33) was deflationary. Japan fought mild deflation for most of the 1990s–2010s. Central banks target a small positive inflation rate to keep a safe cushion above zero.
Since 2012, the Federal Open Market Committee has formally targeted 2% inflation as measured by the annual change in the PCE price index. In 2020 the Fed adopted an "average inflation targeting" framework, saying it would tolerate periods above 2% to offset earlier shortfalls. Through most of the 2010s, PCE inflation ran below 2%; it exceeded 2% sharply during 2021–2023.
CPI measures a fixed basket for the average urban household. Your personal inflation depends on what you actually spend on. If a large share of your budget is housing, healthcare, education, or childcare — all of which have historically risen faster than headline CPI — your lived inflation is higher than the headline number.
All CPI values come from the U.S. Bureau of Labor Statistics, series CUUR0000SA0, not seasonally adjusted, base 1982-84 = 100. We publish the full annual dataset at /calculators/data/cpi-annual.json — free and downloadable. Data is refreshed each January after BLS finalizes the previous year's annual average.