I Bonds Calculator — Value, Interest & Early-Redemption Penalty

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I Bonds

Value • Interest • Penalty

Amount invested

Composite annual rate ⓘ

Years held

yrs

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Enter your bond to see its value

How the I Bonds Calculator Works

Enter the amount you put into Series I bonds.
Enter the composite rate (from TreasuryDirect) and how long you've held them.
See the value, interest, and penalty if you cash out before 5 years.

How Series I Savings Bonds Work

I bonds are inflation-protected US savings bonds. They earn a composite rate = a fixed rate (set at purchase, kept for the bond's life) plus a variable inflation rate that resets every six months. Interest compounds semiannually and is exempt from state and local tax. You can buy up to $10,000 per person per year electronically.

You can't redeem in the first 12 months, and if you cash out before 5 years you forfeit the last 3 months of interest. After 5 years there's no penalty. This calculator estimates value assuming a steady composite rate — your actual rate changes each six months. Estimate only, not investment advice.

I Bonds FAQ

When can I cash in an I bond? ▾

After 12 months. If you redeem before 5 years you lose the last 3 months of interest; after 5 years there's no penalty. I bonds stop earning interest after 30 years.

How much can I buy in I bonds? ▾

Up to $10,000 per person per calendar year in electronic I bonds through TreasuryDirect (plus a possible paper allotment via your tax refund).

Are I bonds taxed? ▾

Interest is exempt from state and local tax and is federally taxable — but you can defer the federal tax until you redeem or the bond matures.

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