$640 in 1921 is equivalent in purchasing power to about $9,807.73 today, an increase of $9,167.73 over 100 years. The dollar had an average inflation rate of 2.77% per year between 1921 and today, producing a cumulative price increase of 1,432.46%.

This means that today's prices are 15.32 times higher than average prices since 1921, according to the Bureau of Labor Statistics consumer price index. A dollar today only buys 6.53% of what it could buy back then.

The 1921 inflation rate was -10.50%. The current year-over-year inflation rate (2020 to 2021) is now 5.39%^{1}.
If this number holds, $640 today will be equivalent in buying power to $674.50 next year.
The current inflation rate page gives more detail on the latest inflation rates.

Contents

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Cumulative price change | 1,432.46% |

Average inflation rate | 2.77% |

Converted amount ($640 base) | $9,807.73 |

Price difference ($640 base) | $9,167.73 |

CPI in 1921 | 17.900 |

CPI in 2021 | 274.310 |

Inflation in 1921 | -10.50% |

Inflation in 2021 | 5.39% |

$640 in 1921 | $9,807.73 in 2021 |

This chart shows a calculation of buying power equivalence for $640 in 1921 (price index tracking began in 1635).

For example, if you started with $640, you would need to end with $9,807.73 in order to "adjust" for inflation (sometimes refered to as "beating inflation").

When $640 is equivalent to $9,807.73 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 1921 dollars, the chart below shows how $640 is worth less over 100 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 1921 amounts in today's dollars, based on the 1,432.46% change in prices:

Initial value | Equivalent value |
---|---|

$1 dollar in 1921 | $15.32 dollars today |

$5 dollars in 1921 | $76.62 dollars today |

$10 dollars in 1921 | $153.25 dollars today |

$50 dollars in 1921 | $766.23 dollars today |

$100 dollars in 1921 | $1,532.46 dollars today |

$500 dollars in 1921 | $7,662.29 dollars today |

$1,000 dollars in 1921 | $15,324.58 dollars today |

$5,000 dollars in 1921 | $76,622.91 dollars today |

$10,000 dollars in 1921 | $153,245.81 dollars today |

$50,000 dollars in 1921 | $766,229.05 dollars today |

$100,000 dollars in 1921 | $1,532,458.10 dollars today |

$500,000 dollars in 1921 | $7,662,290.50 dollars today |

$1,000,000 dollars in 1921 | $15,324,581.01 dollars today |

Inflation can vary widely by city, even within the United States. Here's how some cities fared in 1921 to 2021 (figures shown are purchasing power equivalents of $640):

**San Francisco, California**: 3.03% average rate, $640 → $12,646.10, cumulative change of 1,875.95%**Seattle, Washington**: 2.88% average rate, $640 → $10,982.24, cumulative change of 1,615.98%**New York**: 2.80% average rate, $640 → $10,108.67, cumulative change of 1,479.48%**Boston, Massachusetts**: 2.78% average rate, $640 → $9,955.24, cumulative change of 1,455.51%**Philadelphia, Pennsylvania**: 2.70% average rate, $640 → $9,144.83, cumulative change of 1,328.88%**Chicago, Illinois**: 2.67% average rate, $640 → $8,888.07, cumulative change of 1,288.76%**Houston, Texas**: 2.64% average rate, $640 → $8,657.04, cumulative change of 1,252.66%**Atlanta, Georgia**: 2.62% average rate, $640 → $8,485.99, cumulative change of 1,225.94%**Detroit, Michigan**: 2.56% average rate, $640 → $8,023.50, cumulative change of 1,153.67%

San Francisco, California experienced the highest rate of inflation during the 100 years between 1921 and 2021 (3.03%).

Detroit, Michigan experienced the lowest rate of inflation during the 100 years between 1921 and 2021 (2.56%).

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

Inflation can also vary widely by country. For comparison, in the UK £640.00 in 1921 would be equivalent to £32,137.17 in 2021, an absolute change of £31,497.17 and a cumulative change of 4,921.43%.

In Canada, CA$640.00 in 1921 would be equivalent to CA$9,354.89 in 2021, an absolute change of CA$8,714.89 and a cumulative change of 1,361.70%.

Compare these numbers to the US's overall absolute change of $9,167.73 and total percent change of 1,432.46%.

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 1921 and 2021.

Compare these values to the overall average of 2.77% per year:

Category | Avg Inflation (%) | Total Inflation (%) | $640 in 1921 → 2021 |
---|---|---|---|

Food and beverages | 3.89 | 4,426.59 | 28,970.15 |

Housing | 4.16 | 5,809.21 | 37,818.94 |

Apparel | 1.35 | 280.90 | 2,437.76 |

Transportation | 3.27 | 2,398.43 | 15,989.93 |

Medical care | 4.69 | 9,656.93 | 62,444.36 |

Recreation | 1.13 | 208.57 | 1,974.86 |

Education and communication | 1.83 | 514.24 | 3,931.13 |

Other goods and services | 4.94 | 12,326.01 | 79,526.43 |

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 1921. This table and charts use the earliest available data for each category.

Our calculations use the following inflation rate formula to calculate the change in value between 1921 and today:

CPI today
CPI in 1921

×

1921 USD value

=

Today's value

Then plug in historical CPI values. The U.S. CPI was 17.9 in the year 1921 and 274.31 in 2021:

274.3117.9

×

$640

=

$640 in 1921 has the same "purchasing power" or "buying power" as $9,807.73 in 2021.

To get the total inflation rate for the 100 years between 1921 and 2021, we use the following formula:

CPI in 2021 - CPI in 1921CPI in 1921

×

100

=

Plugging in the values to this equation, we get:

274.31 - 17.917.9

×

100

=

The average inflation rate of 2.77% has a compounding effect between 1921 and 2021. As noted above, this yearly inflation rate compounds to produce an overall price difference of 1,432.46% over 100 years.

To help put this inflation into perspective, if we had invested $640 in the S&P 500 index in 1921, our investment would be * nominally* worth approximately $18,925,989.30 in 2021. This is a return on investment of 2,957,085.83%, with an absolute return of $18,925,349.30 on top of the original $640.

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 93.47% of returns ($17,690,980.70) during this period. This means the inflation-adjusted * real* return of our $640 investment is $1,234,368.60. You may also want to account for capital gains tax, which would take your real return down to around $1,049,213 for most people.

Original Amount | Final Amount | Change | |
---|---|---|---|

Nominal |
$640 | $18,925,989.30 | 2,957,085.83% |

RealInflation Adjusted |
$640 | $1,235,008.60 | 192,870.09% |

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 1921 to latest available data for 2021 using average monthly close price.

For more details on the S&P 500 between 1921 and 2021, see the stock market returns calculator.

Politics and news often influence economic performance. Here's what was happening at the time:

- The Chinese Communist Party is founded by Chen Duxiu.
- Alice Mary Robertson becomes the first woman to preside over the United States House of Representatives.
- Adolf Hitler is declared leader of the National Socialist German Workers Party.

Raw data for these calculations comes from the Bureau of Labor Statistics' Consumer Price Index (CPI), established in 1913. Inflation data from 1665 to 1912 is sourced from a historical study conducted by political science professor Robert Sahr at Oregon State University.

You may use the following MLA citation for this page: “$640 in 1921 → 2021 | Inflation Calculator.” Official Inflation Data, Alioth Finance, 20 Oct. 2021, https://www.officialdata.org/us/inflation/1921?amount=640.

Special thanks to QuickChart for their chart image API, which is used for chart downloads.

in2013dollars.com is a reference website maintained by the Official Data Foundation.

Cumulative price change | 1,432.46% |

Average inflation rate | 2.77% |

Converted amount ($640 base) | $9,807.73 |

Price difference ($640 base) | $9,167.73 |

CPI in 1921 | 17.900 |

CPI in 2021 | 274.310 |

Inflation in 1921 | -10.50% |

Inflation in 2021 | 5.39% |

$640 in 1921 | $9,807.73 in 2021 |