The composite interest rate for I bonds issued from November 2024 through April 2025 is currently 3.11%. This rate is a combination of a fixed rate and an inflation rate.
How the I Bond Composite Rate as of Today is Calculated
The I Bond Rate As Of Today is determined using a specific formula that incorporates both a fixed rate and a semiannual inflation rate. Here’s a breakdown:
| Component | Rate |
|---|---|
| Fixed Rate | 1.20% |
| Semiannual Inflation Rate | 0.95% |
The composite rate is calculated as follows:
Composite Rate = [Fixed Rate + (2 x Semiannual Inflation Rate) + (Fixed Rate x Semiannual Inflation Rate)]
Applying the current rates:
[0.0120 + (2 x 0.0095) + (0.0120 x 0.0095)] = 0.031114
Rounding to two decimal places results in a composite rate of 3.11%.
When I Bond Interest Rates Change
While new I Bond rates are announced in May and November, the rate for a specific bond changes every six months from its issue date. Here’s a table outlining when rate changes take effect:
| Issue Month | Rate Change Dates |
|---|---|
| January | July 1 and January 1 |
| February | August 1 and February 1 |
| March | September 1 and March 1 |
| April | October 1 and April 1 |
| May | November 1 and May 1 |
| June | December 1 and June 1 |
| July | January 1 and July 1 |
| August | February 1 and August 1 |
| September | March 1 and September 1 |
| October | April 1 and October 1 |
| November | May 1 and November 1 |
| December | June 1 and December 1 |
How I Bond Interest Accrues
I bonds begin earning interest from the first day of their purchase month. Interest is compounded semiannually, meaning it’s added to the principal twice a year. This compounding effect allows earnings to grow on an increasing balance.
For bonds held less than five years, the final three months of earned interest are not paid out if the bond is redeemed before maturity. You can find the current value of your I bonds in your TreasuryDirect account or by using the Savings Bond Calculator for paper bonds.
Historical I Bond Rates
Historical rates for I bonds, including fixed, inflation, and composite rates, are available in comprehensive charts and spreadsheets on the TreasuryDirect website. These resources allow you to track the complete rate history for specific bonds.
Fixed Rate History
The fixed rate component of the I Bond remains constant for the life of the bond. The table below shows the historical fixed rates:
| Date Set | Fixed Rate |
|---|---|
| November 1, 2024 | 1.20% |
| May 1, 2024 | 1.30% |
Inflation Rate History
The inflation rate component of the I Bond is adjusted every six months for all outstanding I bonds. Below are some historical inflation rates:
| Date Set | Inflation Rate |
|---|---|
| November 1, 2024 | 0.95% |
| May 1, 2024 | 1.48% |
Composite Rate History
| Period | Composite Rate |
|---|---|
| Nov. 2024 – Apr. 2025 | 3.11% |
| May 2024 – Oct. 2024 | 3.21% |
