Savings Bond Value Calculator
Project how a U.S. savings bond grows with semiannual compounding — see its future redemption value and total interest earned.
How it works
Value = principal × (1 + rate ÷ 2)^(years × 2) · Interest = value − principal
U.S. savings bonds accrue interest that is added to the bond and compounds every six months, so the effective growth is a little faster than simple annual interest at the same headline rate. Series I bonds reset their rate each six months for inflation, while Series EE bonds carry a fixed rate; this tool uses whatever single rate you enter over the full period. Remember that bonds cashed within the first five years forfeit the last three months of interest.
Worked example
A $1,000 bond earning 4% has a semiannual rate of 2%. Over 10 years that is 20 compounding periods: 1,000 × 1.02^20 ≈ $1,485.95, so about $485.95 of interest.
Sources: TreasuryDirect — Savings bonds
Frequently asked questions
How often do savings bonds compound?
Interest is credited and compounds semiannually — every six months — and is added to the bond's value rather than paid out. You receive all the accrued interest when you redeem the bond.
Is there a penalty for cashing early?
Yes. If you redeem a savings bond within the first five years you lose the most recent three months of interest. After five years you can cash it with no penalty.
What rate should I enter?
Enter the composite rate the bond is currently earning. Series I rates change every six months, so an average or the current rate gives a projection rather than an exact figure.
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Educational estimate, not investment advice. Options and margin involve substantial risk.