Updated August 2026
Savings bonds don't pay interest the way a savings account does — there's no monthly deposit, and for decades there was no visible statement at all. Instead, the bond's redemption value itself grows on a published schedule, and cashing it later simply realizes whatever it has grown to. Here's the mechanism behind that growth.
Across every series still relevant today — EE, I, and the now-matured E — interest compounds twice a year. Each redemption value published by the Treasury already reflects all compounding up to that point; you never need to calculate compounding yourself, but understanding that it's semiannual (not daily, not annual) explains why a bond's value moves in visible steps rather than smoothly.
The two active series use different rate structures. EE bonds issued since May 2005 earn a single fixed rate, set the month of purchase and held for the bond's entire life. I bonds earn a composite rate — a fixed portion set at purchase, combined with an inflation-linked portion that resets every May and November for all I bonds outstanding. See the full EE vs. I comparison for how that plays out in practice.
Cash any EE or I bond before it's 5 years old and you forfeit the most recent 3 months of interest — this is standard across both series and is already built into the redemption values you'll see, so the figure shown is exactly what you'd receive today, penalty included. After 5 years, there's no penalty at all.
Neither EE nor I bonds can be redeemed at all in their first 12 months — this isn't a penalty, it's a hard lock. A bond issued 8 months ago simply isn't redeemable yet, regardless of how much interest has notionally accrued.
EE bonds issued since June 2003 carry a guarantee: if regular compounding hasn't brought the bond to double its purchase price by the 20-year mark, the Treasury makes a one-time top-up adjustment so it does. This is unique to EE bonds — I bonds have no equivalent guarantee, since their composite rate already tracks inflation directly.
Every bond has a final maturity date — 30 years from issue for EE and I bonds — after which it permanently stops earning any further interest. The bond's value freezes at whatever it reached, and it can still be cashed for that frozen amount at any time; see when savings bonds mature and how to cash old savings bonds for what to do with one.
Because rates vary by issue era, compounding is semiannual rather than continuous, penalties apply below 5 years, and EE bonds carry a one-time adjustment at 20 years, hand-calculating a bond's exact value from its nominal rate alone is genuinely error-prone. That's why the Treasury publishes finished, penalty-adjusted redemption tables rather than a formula — and why this calculator reads those tables directly instead of re-deriving the math. Full detail on that process is on the How We Calculate page.