Monthly (Standard TFCU)
Daily
Quarterly
Annually
At Maturity (Simple Interest)
Initial Deposit:$0.00
Total Interest Earned:$0.00
Total Balance at Maturity:$0.00
*Estimates based on the dividend rate provided. Actual returns at TFCU may vary slightly based on specific share certificate terms.
function calculateTFCUResults() {
// 1. Get Input Values by ID strictly matching HTML
var depositInput = document.getElementById("depositAmount").value;
var monthsInput = document.getElementById("termMonths").value;
var rateInput = document.getElementById("dividendRate").value;
var freqInput = document.getElementById("compoundingFreq").value;
var resultBox = document.getElementById("tfcuResultBox");
// 2. Parse values to numbers
var principal = parseFloat(depositInput);
var months = parseFloat(monthsInput);
var ratePercent = parseFloat(rateInput);
var frequency = parseInt(freqInput);
// 3. Validation
if (isNaN(principal) || principal < 0) {
alert("Please enter a valid deposit amount.");
return;
}
if (isNaN(months) || months <= 0) {
alert("Please enter a valid term length in months.");
return;
}
if (isNaN(ratePercent) || ratePercent < 0) {
alert("Please enter a valid dividend rate or APY.");
return;
}
// 4. Calculation Logic
var r = ratePercent / 100; // Annual rate in decimal
var t = months / 12; // Time in years
var finalBalance = 0;
// Handle "At Maturity" (Simple Interest) vs Compounding
if (frequency === 0) {
// Simple Interest: A = P(1 + rt)
finalBalance = principal * (1 + (r * t));
} else {
// Compound Interest: A = P(1 + r/n)^(nt)
// n = frequency, t = years
var n = frequency;
finalBalance = principal * Math.pow((1 + (r / n)), (n * t));
}
var totalInterest = finalBalance – principal;
// 5. Update UI
document.getElementById("displayDeposit").innerHTML = "$" + principal.toLocaleString("en-US", {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("displayInterest").innerHTML = "$" + totalInterest.toLocaleString("en-US", {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("displayTotal").innerHTML = "$" + finalBalance.toLocaleString("en-US", {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Show result box
resultBox.style.display = "block";
}
Understanding Tinker Federal Credit Union (TFCU) CD Rates
When looking to grow your savings in Oklahoma, Tinker Federal Credit Union (TFCU) offers "Share Certificates," commonly known as Certificates of Deposit (CDs) at traditional banks. These investment vehicles allow members to earn a higher dividend rate compared to standard savings accounts in exchange for locking the funds away for a specific term length.
How to Use This Calculator
This calculator is designed to help TFCU members estimate the future growth of their Share Certificates. Here is how to interpret the input fields:
Opening Deposit Amount: The total sum of money you plan to invest in the certificate. TFCU typically has minimum deposit requirements (often $1,000 for standard certificates) which may affect the rate you qualify for.
Term Length (Months): How long you agree to keep the money in the account. TFCU terms often range from 6 months up to 60 months (5 years) or more.
Dividend Rate / APY: Enter the current rate offered by TFCU. Note that while APY (Annual Percentage Yield) reflects the total amount of interest paid on an account based on the interest rate and the frequency of compounding for a 365-day period, the Dividend Rate is the annualized rate without compounding. For estimation purposes, entering the advertised APY is usually sufficient.
Compounding Frequency: TFCU Share Certificates typically compound dividends monthly. This means your earnings are added to your balance every month, and future dividends are calculated on that new, higher balance.
Why Choose a TFCU Share Certificate?
As the largest credit union in Oklahoma, TFCU is member-owned and not-for-profit. This structure often allows them to return profits to members in the form of higher savings rates and lower loan rates.
Share certificates are a low-risk investment. Your principal is federally insured by the NCUA (National Credit Union Administration) up to $250,000, similar to how the FDIC insures bank deposits. This makes TFCU certificates an excellent choice for conservative investors looking to combat inflation without risking their capital in the stock market.
Calculating Your Returns
The growth of your money depends heavily on the compounding frequency. The mathematical formula used for monthly compounding is:
A = P(1 + r/n)^(nt)
Where P is your deposit, r is the annual rate, n is the number of times compounded per year (12 for monthly), and t is the time in years. This calculator performs this math instantly to show you exactly how much interest your money will generate over the life of the certificate.