See what your Series I savings bond is worth today. Enter the amount and purchase month: the calculator applies the fixed rate locked in at purchase and each period's inflation rate, compounds the value every six months, and subtracts the 3-month interest penalty if you cash out before 5 years.
Last updated:
$
Purchase price ($25 minimum electronic, $10,000 yearly limit per person)
Interest starts on the first day of the purchase month
% / 6 mo
Semiannual rate used for periods after the last rate in the table
From TreasuryDirect announcements (each May and November). Add new lines as rates are announced.
Enter your values to see the result.
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How to use the I Bond Calculator
Enter the amount you paid for the bond.
Enter the purchase date; only the month matters, because I bonds earn interest from the first day of the issue month.
Choose the valuation date (today by default) and an assumed inflation rate for periods not yet announced.
Press Calculate value to see the value, interest, penalty, current rate and key dates.
Keep the rates current: add a line to the rate history each May and November when new rates are announced.
How I bond value is calculated
Fixed rate: set on the purchase date and kept for the life of the bond (up to 30 years).
Semiannual inflation rate: the change in the CPI-U over six months, announced each May and November.
Composite rate = fixed + 2 × semiannual inflation + fixed × semiannual inflation, rounded to two decimals and never below 0%.
Compounding: every six months from the issue month the value grows by composite ÷ 2. Within a period, interest is added each month as start value × (1 + composite ÷ 2)months ÷ 6.
Penalty: before 5 years, the value is taken from 3 months earlier, which removes the last 3 months of interest.
Recent I bond rates
Announced for bonds bought
Fixed rate
Semiannual inflation
Composite rate
Nov 2025 – Apr 2026
0.90%
1.56%
4.03%
May 2025 – Oct 2025
1.10%
1.43%
3.98%
Nov 2024 – Apr 2025
1.20%
0.95%
3.11%
May 2024 – Oct 2024
1.30%
1.48%
4.28%
Nov 2023 – Apr 2024
1.30%
1.97%
5.27%
May 2023 – Oct 2023
0.90%
1.69%
4.30%
Nov 2022 – Apr 2023
0.40%
3.24%
6.89%
May 2022 – Oct 2022
0.00%
4.81%
9.62%
Nov 2021 – Apr 2022
0.00%
3.56%
7.12%
The composite rate shown is for new purchases. Older bonds combine the same inflation rate with their own fixed rate. The full history since May 2010 is in the calculator's rate box; add newly announced rates there.
Tips for I bond holders
Cash out just after a month starts: interest is credited on the first day of each month, so redeeming late in a month gives no extra interest.
Mind the 3-month penalty: before year 5, cashing right after three low-rate months costs less than cashing after three high-rate months.
Compare fixed rates: a bond with a higher fixed rate keeps beating inflation by that margin for up to 30 years.
Buying late in a month still earns interest for the whole month, which is why the calculator only uses the purchase month.
Frequently asked questions
How is the I bond rate calculated?
The composite rate combines a fixed rate set when you buy and a semiannual inflation rate reset every May and November: composite = fixed + (2 × semiannual inflation) + (fixed × semiannual inflation). For example, a 0.90% fixed rate with a 1.56% semiannual inflation rate gives 0.90 + 3.12 + 0.014 ≈ 4.03%.
When does my I bond's rate change?
Every six months from the issue date, not on the announcement date. A bond bought in February gets a new rate every February and August, using the inflation rate announced the previous November or May.
What is the I bond early withdrawal penalty?
You cannot cash an I bond in the first 12 months. If you cash it before it is 5 years old, you lose the last 3 months of interest. After 5 years there is no penalty. The bond earns interest for up to 30 years.
Can an I bond lose value?
No. If deflation makes the composite rate negative, it is set to 0% for that period, so the bond's value never falls. In May 2015, for example, the semiannual inflation rate was −0.80% and bonds with a 0% fixed rate earned 0% for six months.
How is I bond interest taxed?
Interest is subject to federal income tax but exempt from state and local income tax. You can report it every year or defer it until you cash the bond or it matures. It may be tax free if used for qualified higher education expenses and you meet the conditions.
How much can I buy?
Up to $10,000 in electronic I bonds per person each calendar year through TreasuryDirect. Paper I bonds through a federal tax refund were limited to $5,000 a year. These limits have been in place for years but can change, so check TreasuryDirect before buying.
Why might my value differ from TreasuryDirect?
The Treasury calculates values per $25 and rounds at each step, and older paper bonds use slightly different rounding. This calculator follows the same method, but results can differ by a few cents. Values for future periods depend on your assumed inflation rate.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.