Use this calculator to estimate the future value of your U.S. Savings Bonds based on an assumed average annual interest rate. This tool provides a projection and is not an official valuation from TreasuryDirect.
Understanding U.S. Savings Bonds
United States Savings Bonds are low-risk savings products issued by the U.S. Department of the Treasury. They are a way for individuals to lend money to the government, earning interest over time. The two most common types are Series EE and Series I bonds.
Series EE Bonds
Series EE bonds are purchased at face value and earn a fixed interest rate for 20 years. They are guaranteed to double in value if held for 20 years. After 20 years, they continue to earn interest at a variable rate for another 10 years, reaching final maturity at 30 years.
Series I Bonds
Series I bonds are also purchased at face value but earn a composite interest rate that combines a fixed rate and an inflation rate. This makes them attractive during periods of high inflation, as their value keeps pace with rising costs. Like EE bonds, they earn interest for up to 30 years.
How Interest Accrues
Interest on savings bonds accrues monthly and is compounded semiannually. This means that the interest earned in one six-month period is added to the bond's principal, and the next six months' interest is calculated on the new, larger principal. This compounding effect helps your investment grow faster over time.
Using This Calculator
This calculator provides an estimation of your bond's future value based on an assumed average annual interest rate. It's important to understand that actual savings bond interest rates can vary significantly based on the bond series, purchase date, and for Series I bonds, the prevailing inflation rate. For precise, up-to-date values of your specific bonds, you should always refer to your account on TreasuryDirect.gov.
Example Calculation:
Let's say you purchased a $1,000 bond in 2015 and want to estimate its value after 10 years, assuming an average annual interest rate of 3.5%:
Original Bond Face Value: $1,000
Bond Purchase Year: 2015
Years to Project Value: 10 (meaning you want to see its value in 2025)
Assumed Average Annual Interest Rate: 3.5%
Using the formula: Future Value = Principal * (1 + Rate)^Years
Future Value = $1,000 * (1 + 0.035)^10
Future Value = $1,000 * (1.035)^10
Future Value ≈ $1,000 * 1.41059876
Future Value ≈ $1,410.60
The estimated value of your bond after 10 years would be approximately $1,410.60, with $410.60 in estimated interest earned.
';
output += 'Original Face Value: $' + purchaseAmount.toFixed(2) + '';
output += 'Purchase Year: ' + purchaseYear + '';
output += 'Projected to Year: ' + projectionYear + ' (after ' + yearsToProject + ' years)';
output += 'Assumed Average Annual Rate: ' + assumedAnnualRate.toFixed(2) + '%';
output += 'Estimated Current Value: $' + estimatedValue.toFixed(2) + '';
output += 'Estimated Total Interest Earned: $' + totalInterest.toFixed(2) + '';
if (yearsToProject >= 20) {
output += 'Note: Series EE bonds are guaranteed to double in value if held for 20 years. This calculation uses your assumed rate for projection.';
}
output += 'Disclaimer: This is an estimation. Actual bond values depend on specific bond series, purchase dates, and official Treasury rates. For precise values, consult TreasuryDirect.gov.';
resultDiv.innerHTML = output;
}