Series EE Savings Bond Calculator
How the Series EE Bond Calculator Works
Series EE savings bonds are low-risk savings products issued by the U.S. Treasury. This calculator estimates the growth of your bond based on the purchase price and the fixed interest rate. Since May 2005, Series EE bonds are purchased at face value, meaning if you pay $1,000, the bond is worth $1,000 on day one.
The 20-Year Doubling Guarantee
One of the most unique features of Series EE bonds is the Treasury's guarantee. If you hold a bond for 20 years, the U.S. Treasury guarantees that the bond will be worth at least double its purchase price. If the accumulated interest over those 20 years does not double the bond's value, the Treasury makes a one-time adjustment to fulfill the guarantee.
Calculation Formula
The interest on Series EE bonds is earned monthly and compounded semiannually. The basic formula for the growth (excluding the one-time 20-year adjustment) is:
A = P (1 + r/n)^(nt)
- A = Final Amount
- P = Purchase Price
- r = Annual Interest Rate (decimal)
- n = Compounding periods per year (2 for EE Bonds)
- t = Number of years held
Series EE Bond Example Growth
| Purchase Price | Fixed Rate | Years Held | Final Value |
|---|---|---|---|
| $5,000 | 2.10% | 10 Years | $6,155.24 |
| $5,000 | 2.10% | 20 Years | $10,000.00* |
| $5,000 | 2.10% | 25 Years | $11,098.80 |
*Value adjusted to double the purchase price per Treasury guarantee.
Important Considerations
When using the Series EE Bond calculator, keep in mind that these bonds earn interest for up to 30 years. If you cash them in before 5 years, you will typically lose the last three months of interest as a penalty. These bonds are non-marketable, meaning they cannot be sold to other investors; they must be redeemed through the Treasury.