Inflation and I Bond

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The I Bond Calculator

Use the I Bond Calculator to get monthly values of your I bond investment. Get a graphical comparison of your I bond's growth to inflation. Download monthly values in CSV format.

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August 14, 2024

Comparing I Bonds to Inflation

If you hold I bonds for five years or longer you will get the full interest when you redeem them. As of August 1, 2024, there are 251 I bonds that are older than five years. These are the I bonds purchased from September 1998 through July 2019, the five year mark as of August 2024. Of these 251 I bonds, 199 will provide a real return if you redeem them in August. In other words, 199 of these I bonds had grown in their values to exceed their inflation-adjusted purchase prices and the remaining 52 are lagging behind inflation. The I bond purchased in May 2000 has the highest return (141.53%), while your February 2015 purchase has the lowest return (-2.44%).

For I bonds with fixed rate greater than zero, a higher percentage of the bonds is above inflation-adjusted levels, as shown in the graph below.

For I bonds purchased each month starting from September 1998 through July 2019, the chart below shows how much the bonds had grown in values compared to the growth in inflation for the same period. The variance shown in the graph is the difference between the bond value and the inflation-adjusted purchase price on 8/1/2024 as a percentage of the inflation-adjusted purchase price. So it is the cumulative real growth from the purchase date through 8/1/2024 (not annual growth). As an example, as on 8/1/2024, a \$10,000 I bond purchased in September 1998 had grown 139.48% over its inflation-adjusted purchase price.

Use the Next and Previous buttons to move around the purchase dates of bonds.

I Bonds 5 Years or Older: Sept 1998 - July 2019

Use the buttons to change dates

I Bonds Over Time

The chart below shows the number of I bonds older than five years above and below their inflation-adjusted purchase prices for each month from January 2020 through August 2024. For example, in January 2020, there were 196 I bonds older than 5 years. Out of them, 193 had grown in their values to exceed their respective purchase prices adjusted for inflation, and only three were below those levels. On the other hand, in August 2024, 199 out of a total of 251 I bonds (79%) older than five years were above and 52 were below their inflation-adjusted purchase prices.

Click on a legend to toggle a dataset.

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Create a Summary of All Your I Bonds

Use this tool to generate a table summarizing all your I bonds as of the first of the current month. The table will list out the following information:

• Purchase date
• Purchase amount
• Fixed interest
• Accrued value, and
• Redemption value.

An additional column will contain a link to the details of the individual I bonds. A copy button makes it easy to copy and paste the generated table into Microsoft Excel or other applications.

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Track I Bond in Quicken and Moneydance
Generate price history files for I bonds. Upload these files to Quicken or Moneydance to track them in these two programs.

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Track All Your I Bonds in Excel
A spreadsheet solution to track all your I bonds and get the accrued value, redemption value, and fixed rate on any date.

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