Inflation and I Bond

New!
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.

Start here
Inflation Calculator

May 13, 2025

Comparing I Bonds to Inflation

If you hold I bonds for five years or more, you'll receive the full interest when you redeem them. As of May 1, 2025, there are 261 I bonds that are older than five years, purchased between September 1998 and May 2020. Out of these, 204 will provide a real return if redeemed in May, meaning their values have increased beyond their inflation-adjusted purchase prices. The remaining 57 have not kept up with inflation, primarily due to the time lag in the inflation adjustment reflecting in the I bond rates. The I bond purchased in May 2000 boasts the highest return at 147.31%, while the February 2015 purchase shows the lowest return at -2.45%.

For I bonds with a fixed rate above zero, a larger percentage of these bonds exceeds inflation-adjusted levels, as illustrated in the graph below.

The chart below illustrates the growth of I bonds purchased monthly from September 1998 to May 2020, compared to inflation during the same period. The variance depicted in the graph represents the difference between the bond value and the inflation-adjusted purchase price as of 5/1/2025, expressed as a percentage of that adjusted price. This reflects the cumulative real growth from the purchase date to 5/1/2025, rather than annual growth.

For instance, as of 5/1/2025, a $10,000 I bond bought in September 1998 had increased by 146% compared to 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 - May 2020

Use the buttons to change dates

I Bonds Over Time

The chart below illustrates the number of I bonds older than five years in relation to their inflation-adjusted purchase prices from January 2020 to May 2025. For instance, in January 2020, there were 196 I bonds over five years old, with 193 surpassing their inflation-adjusted purchase prices and only three falling below that threshold.

In contrast, by May 2025, out of 261 I bonds older than five years, 204 (78%) exceeded their inflation-adjusted purchase prices, while 57 were below.

Click on a legend to toggle a dataset.

New!
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.

Start here
New!
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.

Start here
New!
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.

Start here

More Calculators

Select the calculator that meets your needs

...
New!
Mortgage Amortization

Create a mortgage amortization schedule and get a graphical view of your loan pay down.

...
New!
Car Loan Payment

Calculate car loan payment and generate a payment schedule for your car loan.

...
New!
Savings Calculator

Find out how much you can save over a period of time.

...
New!
Retirement Calculator

Find out how long will your retirement savings last. Create a draw-down schedule based on a given growth rate and inflation rate.

...
New!
Present Value Calculator

Calculate the present value from a given future value.

...
New!
Future Value Calculator

Calculate the future value from a given present value.

All calculators