TreasuryDirect Savings Bond Calculator
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TreasuryDirect Savings Bond Calculator
Enter details to see the bond's estimated value.
Understanding TreasuryDirect Savings Bonds and This Calculator
TreasuryDirect is the U.S. Treasury's savings bond program, offering investors a way to save securely with government backing.
The primary savings bonds currently available or recently expired are Series EE and Series I bonds. Each has unique
interest accrual rules and redemption policies. This calculator provides an *estimation* of your bond's value.
Note: For exact figures, always refer to your official TreasuryDirect account statements or contact TreasuryDirect.
How Savings Bonds Accrue Interest
Savings bonds do not pay interest periodically. Instead, interest is added to the bond's principal value over time.
The interest rate applied depends on the bond type and its issue date.
- Series EE Bonds: Earn a fixed rate for the life of the bond. They are guaranteed to double in value after 20 years.
- Series I Bonds: Earn a combination of a fixed rate and an inflation rate. The inflation rate adjusts semi-annually, while the fixed rate remains the same for the life of the bond.
How This Calculator Works (Simplified Logic)
This calculator aims to estimate the redemption value of your savings bond based on:
- Purchase Price: The initial amount you paid for the bond.
- Issue Date: The date the bond was issued. This is crucial for determining the applicable interest rates and maturity periods.
- Redemption Date: The date you plan to redeem the bond. Interest accrues until this date.
- Bond Type: Series EE and Series I bonds have different interest calculation methods.
The calculation involves determining the number of months the bond has earned interest up to the redemption date.
It then applies historical or current interest rates based on the bond type and issue date to estimate the accumulated value.
Important Limitations:
- This calculator uses simplified interest rate models and may not reflect the exact complex adjustments made by TreasuryDirect, especially for Series I bonds' inflation component.
- Early redemption penalties (if redeeming before 5 years for Series EE/I) are NOT factored in.
- Maturity limits (e.g., 30 years for Series EE/I) are not strictly enforced in this estimation but are important to be aware of.
- This is for educational and estimation purposes only. Always consult official TreasuryDirect resources for definitive financial data.
Example Calculation
Let's say you purchased a Series EE bond for $100 on 2010-06-15 and want to see its estimated value on 2024-06-15.
- Issue Date: 2010-06-15
- Redemption Date: 2024-06-15
- Bond Type: Series EE
- Purchase Price: $100
The calculator would determine the period is 14 years (168 months). It would then look up the interest rates applicable to Series EE bonds issued in June 2010.
These rates are compounded and applied over the 168 months. For Series EE bonds issued between May 2005 and December 2010, the fixed rate was 3.60%.
The bond is also guaranteed to double after 20 years. By 14 years, it would have grown significantly.
This calculator would estimate the value to be approximately $160 – $170 (depending on the exact rate lookup and compounding method used in the script).
For a Series I bond, the calculation would be more complex, factoring in the fixed rate and the semi-annual inflation adjustments which can vary significantly.
function calculateBondValue() {
var purchasePrice = parseFloat(document.getElementById("purchasePrice").value);
var issueDateStr = document.getElementById("issueDate").value;
var redemptionDateStr = document.getElementById("redemptionDate").value;
var bondType = document.getElementById("bondType").value;
var resultDiv = document.getElementById("result");
// Clear previous results and errors
resultDiv.innerHTML = "Calculating…";
// — Input Validation —
if (isNaN(purchasePrice) || purchasePrice <= 0) {
resultDiv.innerHTML = "Error: Please enter a valid purchase price.";
return;
}
if (!issueDateStr || !redemptionDateStr) {
resultDiv.innerHTML = "Error: Please enter both issue and redemption dates.";
return;
}
var issueDate;
try {
issueDate = new Date(issueDateStr);
if (isNaN(issueDate.getTime())) throw new Error("Invalid date format");
} catch (e) {
resultDiv.innerHTML = "Error: Invalid Issue Date format. Use YYYY-MM-DD.";
return;
}
var redemptionDate;
try {
redemptionDate = new Date(redemptionDateStr);
if (isNaN(redemptionDate.getTime())) throw new Error("Invalid date format");
} catch (e) {
resultDiv.innerHTML = "Error: Invalid Redemption Date format. Use YYYY-MM-DD.";
return;
}
if (redemptionDate < issueDate) {
resultDiv.innerHTML = "Error: Redemption date cannot be before the issue date.";
return;
}
// — Interest Rate Data (Simplified & Historical Approximations) —
// These rates are illustrative and simplified. Actual TreasuryDirect rates can be complex.
var rates = {
"Series EE": {
// Fixed rates for Series EE bonds, generally applied for the life of the bond.
// Rates based on issue month/year. This is a simplification.
// Example: For bonds issued May 2005 – Nov 2010, fixed rate was 3.60%
// For bonds issued Dec 2010 – Apr 2011, fixed rate was 2.22%
// … and so on.
// We'll use a representative lookup based on issue year for simplicity.
getRate: function(year) {
if (year = 1995 && year = 1997 && year = 1998 && year = 2002 && year = 2004 && year = 2005 && year = 2011 && year = 2012 && year = 2014 && year = 2015 && year = 2018 && year = 2019 && year = 2021 && year = 2022 && year = 2023 && year = 2024) return 0.025; // Current approximate rate
return 0.00; // Default for unforeseen cases
},
// Series EE doubles after 20 years.
doublingPeriod: 20 * 12 // months
},
"Series I": {
// Series I rates are more complex: a fixed rate + inflation rate.
// Fixed rates have varied. Inflation rate adjusts semi-annually.
// This simplified calculator will use a *representative fixed rate* and *ignore inflation* for estimation.
// For accurate Series I calculations, you'd need historical CPI data and exact fixed rates.
// Representative fixed rates:
getFixedRate: function(year) {
if (year = 1998 && year = 2000 && year = 2003 && year = 2007 && year = 2009 && year = 2011 && year = 2014 && year = 2015 && year = 2016 && year = 2017 && year = 2018 && year = 2019 && year = 2020 && year = 2021 && year = 2022 && year = 2023 && year = 2024) return 0.400; // Current approximate rate
return 0.00;
},
// A simplified inflation factor. For actual calculation, use CPI data.
// Let's assume an average ~2% annual inflation for estimation purposes here.
// This needs semi-annual adjustment, making it very complex for a simple JS calculator.
// We'll approximate by slightly increasing the rate each year.
estimatedAnnualInflationFactor: 1.02
}
};
// — Calculation Logic —
var interestRate;
var currentTermMonths = (redemptionDate.getTime() – issueDate.getTime()) / (1000 * 60 * 60 * 24 * 30.44); // Approximate months
var issueYear = issueDate.getFullYear();
var months = 0;
var currentFaceValue = purchasePrice; // Start with the purchase price
if (bondType === "Series EE") {
interestRate = rates.SeriesEE.getRate(issueYear);
var monthsToMaturity = rates.SeriesEE.doublingPeriod; // 20 years for doubling
for (var i = 0; i = monthsToMaturity && currentFaceValue = rates.SeriesEE.doublingPeriod) {
currentFaceValue = Math.max(currentFaceValue, purchasePrice * 2);
}
resultDiv.innerHTML = "Estimated Value: $" + currentFaceValue.toFixed(2);
} else if (bondType === "Series I") {
var fixedRate = rates.SeriesI.getFixedRate(issueYear);
// For simplification, we'll use the fixed rate and apply a constant 'inflation' factor.
// This is a VERY ROUGH ESTIMATE. Real Series I calculation is complex.
// Assume annual compounding for simplicity:
var estimatedAnnualRate = fixedRate * (1 + (rates.SeriesI.estimatedAnnualInflationFactor – 1)); // Fixed + estimated inflation
for (var year = issueYear; year < redemptionDate.getFullYear(); year++) {
var yearsToCompound = redemptionDate.getFullYear() – issueYear;
currentFaceValue = purchasePrice * Math.pow(1 + estimatedAnnualRate, yearsToCompound);
}
// If redemption is mid-year, we need monthly approximation.
// Calculate for full years, then apply partial year based on monthly rate approximation.
var fullYears = redemptionDate.getFullYear() – issueDate.getFullYear() – (redemptionDate.getMonth() 0) {
currentFaceValue = purchasePrice * Math.pow(1 + estimatedAnnualRate, fullYears);
} else {
currentFaceValue = purchasePrice; // If less than a year, start with principal
}
if (remainingMonths > 0) {
var monthlyRateApprox = Math.pow(1 + estimatedAnnualRate, 1/12) – 1; // Approximate monthly rate
currentFaceValue *= Math.pow(1 + monthlyRateApprox, remainingMonths);
}
resultDiv.innerHTML = "Estimated Value: $" + currentFaceValue.toFixed(2) + " (Simplified)";
}
}