$170 in 1920 is worth $2,681.69 today

Buying power of $170 in 1920

This chart shows a calculation of buying power equivalence for $170 in 1920 (price index tracking began in 1635).

For example, if you started with $170, you would need to end with $2,681.69 in order to "adjust" for inflation (sometimes refered to as "beating inflation").

When $170 is equivalent to $2,681.69 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 1920 dollars, the chart below shows how $170 is worth less over 105 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 1920 amounts in today's dollars, based on the 1,477.46% change in prices:

Inflation by City

Inflation can vary widely by city, even within the United States. Here's how some cities fared in 1920 to 2025 (figures shown are purchasing power equivalents of $170):

• San Francisco, California: 2.95% average rate, $170 → $3,499.95, cumulative change of 1,958.79%
• Seattle, Washington: 2.86% average rate, $170 → $3,176.44, cumulative change of 1,768.49%
• New York: 2.74% average rate, $170 → $2,820.92, cumulative change of 1,559.36%
• Boston, Massachusetts: 2.72% average rate, $170 → $2,777.82, cumulative change of 1,534.01%
• Philadelphia, Pennsylvania: 2.67% average rate, $170 → $2,622.82, cumulative change of 1,442.84%
• Chicago, Illinois: 2.62% average rate, $170 → $2,500.71, cumulative change of 1,371.01%
• Houston, Texas: 2.59% average rate, $170 → $2,435.34, cumulative change of 1,332.55%
• Atlanta, Georgia: 2.58% average rate, $170 → $2,416.19, cumulative change of 1,321.29%
• Detroit, Michigan: 2.54% average rate, $170 → $2,304.78, cumulative change of 1,255.75%

San Francisco, California experienced the highest rate of inflation during the 105 years between 1920 and 2025 (2.95%).

Detroit, Michigan experienced the lowest rate of inflation during the 105 years between 1920 and 2025 (2.54%).

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 £170.00 in 1920 would be equivalent to £9,710.00 in 2025, an absolute change of £9,540.00 and a cumulative change of 5,611.77%.

In Canada, CA$170.00 in 1920 would be equivalent to CA$2,421.66 in 2025, an absolute change of CA$2,251.66 and a cumulative change of 1,324.50%.

Compare these numbers to the US's overall absolute change of $2,511.69 and total percent change of 1,477.46%.

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 1920 and 2025.

Compare these values to the overall average of 2.66% 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 1920. This table and charts use the earliest available data for each category.

How to calculate inflation rate for $170 since 1920

Our calculations use the following inflation rate formula to calculate the change in value between 1920 and today:

Then plug in historical CPI values. The U.S. CPI was 20 in the year 1920 and 315.493 in 2025:

$170 in 1920 has the same "purchasing power" or "buying power" as $2,681.69 in 2025.

To get the total inflation rate for the 105 years between 1920 and 2025, we use the following formula:

Plugging in the values to this equation, we get:

Comparison to S&P 500 Index

The average inflation rate of 2.66% has a compounding effect between 1920 and 2025. As noted above, this yearly inflation rate compounds to produce an overall price difference of 1,477.46% over 105 years.

To help put this inflation into perspective, if we had invested $170 in the S&P 500 index in 1920, our investment would be nominally worth approximately $6,109,255.77 in 2025. This is a return on investment of 3,593,579.86%, with an absolute return of $6,109,085.77 on top of the original $170.

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 93.66% of returns ($5,721,972.64) during this period. This means the inflation-adjusted real return of our $170 investment is $387,113.13. You may also want to account for capital gains tax, which would take your real return down to around $329,046 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 1920 to latest available data for 2025 using average monthly close price.

For more details on the S&P 500 between 1920 and 2025, 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.