Direct Answer
Treasury I Bonds are U.S. government savings bonds with an interest rate that adjusts every 6 months based on CPI inflation. The rate surged to 9.62% (May-October 2022) during peak inflation. The rate for May-October 2024 was 4.28%. I Bonds can be purchased at TreasuryDirect.gov with a $10,000 annual limit per person ($5,000 additional via tax refund).
Treasury I Bond (Series I Savings Bond) Rates
I Bond Composite Rate by 6-Month Period
| Period | Composite Rate | Notes |
|---|---|---|
| Nov 2021 - Apr 2022 | 7.12% | |
| May - Oct 2022 | 9.62% | Peak rate |
| Nov 2022 - Apr 2023 | 6.89% | |
| May - Oct 2023 | 4.30% | |
| Nov 2023 - Apr 2024 | 5.27% | |
| May - Oct 2024 | 4.28% | |
| Nov 2024 - Apr 2025 | ~3.11% | Estimated |
Note: The composite rate = fixed rate + (2 x semiannual inflation rate). The fixed rate component is set at purchase and never changes for the life of the bond. Current fixed rate (May 2024 purchases and later): 1.30%.
Source: TreasuryDirect: I Bond Interest Rates. Last verified: September 2026.
Frequently asked questions
How do I Bond rates work?
I Bond interest has two components: (1) a fixed rate set at purchase time that never changes for the life of the bond; (2) a variable rate that adjusts every 6 months based on CPI-U (All Urban Consumers) inflation. The composite formula: Composite rate = Fixed rate + (2 x Semiannual inflation rate). If CPI was 1.69% for the 6 months (annualized 3.38%), and fixed rate is 1.30%, composite = 1.30% + (2 x 1.69%) = 4.68%. The rate resets every May and November based on the preceding 6-month CPI change. I Bonds purchased at different times carry different fixed rates permanently.
What are the drawbacks of I Bonds?
I Bond limitations include: (1) $10,000 annual purchase limit per person via TreasuryDirect (plus $5,000 via paper bond tax refund); (2) cannot redeem within 12 months of purchase; (3) 3-month interest penalty if redeemed within 5 years; (4) must purchase through TreasuryDirect.gov (no broker intermediary); (5) not tradeable on secondary markets; (6) not held in IRA/401k accounts. The low purchase limit makes I Bonds supplementary rather than a primary savings vehicle for large portfolios. During the 2022 inflation spike, demand was enormous and the site crashed repeatedly.
When is an I Bond better than a Treasury bond or TIPS?
I Bonds are best when: (1) inflation is high or expected to rise (I Bond rates automatically adjust); (2) holding period is 5+ years (avoids the 3-month penalty and maximizes compound inflation protection); (3) amount is within the $10,000 limit (purchase limit makes them a small-portfolio tool). TIPS (Treasury Inflation-Protected Securities) offer unlimited purchase, are tradeable, and can be held in IRAs/401ks. For large inflation hedging needs, TIPS are more practical. For small savers holding savings they won't touch for 5+ years, I Bonds offer compelling inflation protection and government guarantee.
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If you reference this table in your own work, use the following citation format and add the date you accessed it:
Swoopr Editorial Team. (2026). Treasury I Bond (Series I Savings Bond) Rates. Swoopr Investment. https://www.getswoopr.com/tables/bonds/treasury-i-bond-rates/
Check the figures against the primary sources listed under References before you rely on or republish them; the series they come from are revised.