A U.S. Savings Bond matures 12 months after being purchased. After this period the bond may be cashed in for its face value plus accrued interest. The bond earns additional interest beyond the initial one year maturity date, up to 30 years.
When a consumer purchases a U.S. Savings Bond, they are lending the U.S. federal government the sum of the face value of the bond until after the maturity date. The minimum bond denomination is $25, with no maximum. The U.S. Treasury Department, as of 2015, no longer sells paper bonds; all savings bonds are now only in digital format.