Two-Way Conversion
Convert past dollars into today's value, or today's dollars back into any past year.
Official CPI Data
Built on Bureau of Labor Statistics CPI-U annual averages covering 112 years, 1913–2024.
100% In-Browser
All calculations run locally in your browser. No API calls, nothing uploaded.
How Inflation and Purchasing Power Conversion Work
Inflation is the sustained rise in the general price level over time — which means the purchasing power of money steadily falls. The same $100 that filled a grocery cart in 1990 buys far less today. The most widely used measure of inflation is the Consumer Price Index (CPI): statistical agencies track the prices of a fixed basket of everyday goods and services (food, housing, transportation, medical care and more), weight them by typical household spending, and combine them into a single index. The percentage change in that index is the inflation rate.
The conversion formula is straightforward: equivalent value = original amount × (target-year CPI ÷ starting-year CPI). For example, the US CPI annual average was 130.7 in 1990 and 314.2 in 2024, so $100 in 1990 is worth roughly $240 in 2024 — cumulative inflation of about 140%. Swap the years and you can also answer the reverse question: how much would today's money have been worth decades ago? That is handy for reading historical documents, comparing old movie ticket prices, or making sense of the salaries your grandparents mention.
The data comes from the US Bureau of Labor Statistics CPI-U (Consumer Price Index for All Urban Consumers), annual averages with a 1982–84 = 100 base period. The US series is the longest continuously published official inflation record in the world, running since 1913, and the dollar has long served as the international unit of account — which makes it the most useful common yardstick for comparing purchasing power across eras. Keep in mind that CPI reflects average price changes; your personal inflation rate depends on what you actually buy, and items like housing and tuition have often outpaced headline CPI. Use this tool as a starting point for understanding the time value of money when planning savings and investments.
Frequently Asked Questions
What is $100 in 1990 worth today?
Roughly $240 in 2024 dollars. The US CPI annual average rose from 130.7 in 1990 to 314.2 in 2024, a cumulative inflation of about 140% — around 2.6% per year compounded. Enter any amount and year above to run your own comparison.
How is the CPI actually calculated?
The Bureau of Labor Statistics surveys the prices of a representative basket of goods and services — food, rent, transportation, medical care, recreation and more — and weights each category by its share of typical household spending. The weighted average forms the index. With a base period of 1982–84 = 100, a 2024 CPI of 314.2 means the same basket costs about 3.14 times what it did in the base period.
Why does this calculator use US CPI data?
The US CPI is the longest continuously published official inflation series in the world, with consistent annual data back to 1913. The US dollar is also the dominant international unit of account, making it the most practical common yardstick for cross-era purchasing power comparisons. Inflation in other countries can differ significantly, so treat results as US-dollar specific.
How does inflation affect my savings?
Inflation quietly erodes the real purchasing power of cash. At 3% annual inflation, money sitting idle loses about half its purchasing power in 24 years. That is why real (inflation-adjusted) return matters: an investment must earn more than the inflation rate for your purchasing power to actually grow. Holding cash or deposits yielding less than inflation is a guaranteed real loss.
Why was inflation so different across decades?
Inflation is driven by supply and demand, monetary policy, energy prices and wars. Both World Wars brought double-digit US inflation due to shortages; the 1970s oil shocks pushed annual inflation above 13%; the Great Depression of the 1930s saw outright deflation, with prices falling; and 2021–2022 brought a 40-year high driven by post-pandemic supply bottlenecks and loose monetary policy.
Can I convert today's money back to a past year?
Yes. Set the starting year to the present and the target year to the past, or just click the swap button. For example, $1,000 in 2024 is equivalent to about $262 in 1980 — meaning $262 back then bought what $1,000 buys in 2024.
What is the difference between cumulative and annualized inflation?
Cumulative inflation is the total percentage rise in prices over the whole period. Annualized inflation expresses that same rise as a constant compound annual rate, which makes periods of different lengths comparable. For instance, 140% cumulative inflation from 1990 to 2024 works out to about 2.6% per year compounded over 34 years.
Is my data uploaded anywhere?
No. The CPI table is embedded directly in this page and every calculation runs locally in your browser. No external API is called, and the amounts and years you enter never leave your device.