$100 in 1975 is worth $440.55 in 2015

Buying power of $100 in 1975

This chart shows a calculation of buying power equivalence for $100 in 1975 (price index tracking began in 1635).

For example, if you started with $100, you would need to end with $440.55 in order to "adjust" for inflation (sometimes refered to as "beating inflation").

When $100 is equivalent to $440.55 over time, that means that the "real value" of a single U.S. dollar decreases over time. In other words, a dollar will pay for fewer items at the store.

This effect explains how inflation erodes the value of a dollar over time. By calculating the value in 1975 dollars, the chart below shows how $100 is worth less over 40 years.

According to the Bureau of Labor Statistics, each of these USD amounts below is equal in terms of what it could buy at the time:

This conversion table shows various other 1975 amounts in 2015 dollars, based on the 340.55% change in prices:

Inflation by City

Inflation can vary widely by city, even within the United States. Here's how some cities fared in 1975 to 2015 (figures shown are purchasing power equivalents of $100):

• San Francisco, California: 4.12% average rate, $100 → $502.23, cumulative change of 402.23%
• Seattle, Washington: 4.06% average rate, $100 → $490.45, cumulative change of 390.45%
• Boston, Massachusetts: 3.91% average rate, $100 → $464.06, cumulative change of 364.06%
• New York: 3.84% average rate, $100 → $452.29, cumulative change of 352.29%
• Dallas-Fort Worth, Texas: 3.73% average rate, $100 → $433.42, cumulative change of 333.42%
• Chicago, Illinois: 3.73% average rate, $100 → $431.90, cumulative change of 331.90%
• Philadelphia, Pennsylvania: 3.71% average rate, $100 → $428.93, cumulative change of 328.93%
• Houston, Texas: 3.63% average rate, $100 → $416.96, cumulative change of 316.96%
• Atlanta, Georgia: 3.62% average rate, $100 → $415.33, cumulative change of 315.33%
• Detroit, Michigan: 3.57% average rate, $100 → $406.31, cumulative change of 306.31%

San Francisco, California experienced the highest rate of inflation during the 40 years between 1975 and 2015 (4.12%).

Detroit, Michigan experienced the lowest rate of inflation during the 40 years between 1975 and 2015 (3.57%).

Note that some locations showing 0% inflation may have not yet reported latest data.

Inflation by Country

Inflation can also vary widely by country. For comparison, in the UK £100.00 in 1975 would be equivalent to £756.68 in 2015, an absolute change of £656.68 and a cumulative change of 656.68%.

In Canada, CA$100.00 in 1975 would be equivalent to CA$437.19 in 2015, an absolute change of CA$337.19 and a cumulative change of 337.19%.

Compare these numbers to the US's overall absolute change of $340.55 and total percent change of 340.55%.

Inflation by Spending Category

CPI is the weighted combination of many categories of spending that are tracked by the government. Breaking down these categories helps explain the main drivers behind price changes.

This chart shows the average rate of inflation for select CPI categories between 1975 and 2015.

Compare these values to the overall average of 3.78% per year:

The graph below compares inflation in categories of goods over time. Click on a category such as "Food" to toggle it on or off:

For all these visualizations, it's important to note that not all categories may have been tracked since 1975. This table and charts use the earliest available data for each category.

How to calculate inflation rate for $100, 1975 to 2015

Our calculations use the following inflation rate formula to calculate the change in value between 1975 and 2015:

Then plug in historical CPI values. The U.S. CPI was 53.8 in the year 1975 and 237.017 in 2015:

$100 in 1975 has the same "purchasing power" or "buying power" as $440.55 in 2015.

To get the total inflation rate for the 40 years between 1975 and 2015, we use the following formula:

Plugging in the values to this equation, we get:

Alternate Measurements of Inflation

There are multiple ways to measure inflation. Published rates of inflation will vary depending on methodology. The Consumer Price Index, used above, is the most common standard used globally.

Alternative measurements are sometimes used based on context and economic/political circumstances. Below are a few examples of alternative measurements.

Personal Consumption Expenditures (PCE) Inflation

The PCE Price Index is the U.S. Federal Reserve's preferred measure of inflation, compiled by the Bureau of Economic Analysis. It measures the change in prices of goods and services purchased by consumers.

The PCE Price Index changed by 3.27% per year on average between 1975 and 2015. The total PCE inflation between these dates was 262.25%. In 1975, PCE inflation was 8.34%.

This means that the PCE Index equates $100 in 1975 with $362.25 in 2015, a difference of $262.25. Compare this to the standard CPI measurement, which equates $100 with $440.55. The PCE measured -78.31% inflation compared to standard CPI.

For more information on the difference between PCE and CPI, see this analysis provided by the Bureau of Labor Statistics.

Core Inflation

Also of note is the Core CPI, which uses the standard CPI but omits the more volatile categories of food and energy.

Core inflation averaged 3.83% per year between 1975 and 2015 (vs all-CPI inflation of 3.78%), for an inflation total of 349.50%. In 1975, core inflation was 9.21%.

When using the core inflation measurement, $100 in 1975 is equivalent in buying power to $449.50 in 2015, a difference of $349.50. Recall that the converted amount is $440.55 when all items including food and energy are measured.

Comparison to S&P 500 Index

The average inflation rate of 3.78% has a compounding effect between 1975 and 2015. As noted above, this yearly inflation rate compounds to produce an overall price difference of 340.55% over 40 years.

To help put this inflation into perspective, if we had invested $100 in the S&P 500 index in 1975, our investment would be nominally worth approximately $8,618.19 in 2015. This is a return on investment of 8,518.19%, with an absolute return of $8,518.19 on top of the original $100.

These numbers are not inflation adjusted, so they are considered nominal. In order to evaluate the real return on our investment, we must calculate the return with inflation taken into account.

The compounding effect of inflation would account for 77.30% of returns ($6,661.96) during this period. This means the inflation-adjusted real return of our $100 investment is $1,856.22. You may also want to account for capital gains tax, which would take your real return down to around $1,578 for most people.

Information displayed above may differ slightly from other S&P 500 calculators. Minor discrepancies can occur because we use the latest CPI data for inflation, annualized inflation numbers for previous years, and we compute S&P price and dividends from January of 1975 to latest available data for 2015 using average monthly close price.

For more details on the S&P 500 between 1975 and 2015, see the stock market returns calculator.

Data source & citation

Raw data for these calculations comes from the Bureau of Labor Statistics' Consumer Price Index (CPI), established in 1913. Price index data from 1774 to 1912 is sourced from a historical study conducted by political science professor Robert Sahr at Oregon State University and from the American Antiquarian Society. Price index data from 1634 to 1773 is from the American Antiquarian Society, using British pound equivalents.

» Read more about inflation and investment.