The government has recently begun trying to contact owners of fully matured bonds. If some of yours are among them, get thee to your bank forthwith. You can use the savings bond calculator on the Treasury's Bureau of Public Debt's Web site. If you don't want to manage your savings bonds yourself, you can get help. For example, The Savings Bond Informer sends comprehensive monthly statements that include valuations, interest earned, and an analysis of how your bonds are expected to perform in the future.
Interest is added to savings bonds at specific intervals.
If you redeem your bond before the interest is posted, you lose it. For example, if interest is posted in, say, April and October, redeeming bonds in September instead of October would cost you six months' worth of interest. To see when interest is added to your bonds, use these tables . When figuring out what bonds to cash when, you can't go just by date. Older bonds are not by definition worse than newer bonds.