I Bond Calculator
2026 rulesFind what an I bond is worth using the rate it actually earned in each six-month period.
Your numbers
Result
Value in Oct 2026
- Fixed rate for this bond0%
- Value before any penalty$12,005.25
- Interest earned$2,005.25
- Penalty: last 3 months' interest (held under 5 years)-$99.01
- Cash-in value$11,906.25
Interest is free of state and local income tax. Federal tax is due when you cash the bond, or never if it pays qualified college costs and you meet the income limits.
Rate history for this bond
| Six months from | Composite rate | Value after |
|---|---|---|
| May 2022 | 9.62% | $10,481.00 |
| Nov 2022 | 6.48% | $10,820.58 |
| May 2023 | 3.38% | $11,003.45 |
| Nov 2023 | 3.94% | $11,220.22 |
| May 2024 | 2.96% | $11,386.28 |
| Nov 2024 | 1.90% | $11,494.45 |
| May 2025 | 2.86% | $11,658.82 |
| Nov 2025 | 3.12% | $11,840.70 |
| May 2026 | 3.34% | $12,005.25 |
How it works
An I bond earns a composite rate made of its fixed rate, set when you buy and kept for 30 years, plus an inflation rate that resets every May and November. The rate changes every six months from your issue month.
Bonds issued from May through October 2026 earn 4.26%: a 0.90% fixed rate plus 3.34% inflation. Cashing in before five years costs the last three months' interest, and you can't cash in during the first year.
2026 figures: TreasuryDirect Series I rate chart.
Questions
How much can I buy?
$10,000 per person per year in electronic I bonds through TreasuryDirect. Paper I bonds bought with a tax refund were discontinued in 2025.
When is the best time to cash an I bond?
When its current rate falls below what you can earn elsewhere. Older bonds with high fixed rates are worth keeping.