function calculateTBills() {
var principalInput = document.getElementById("principalAmount");
var rateInput = document.getElementById("interestRate");
var durationInput = document.getElementById("duration");
var resultsDiv = document.getElementById("results");
var principal = parseFloat(principalInput.value);
var rate = parseFloat(rateInput.value);
var days = parseInt(durationInput.value);
// Validation
if (isNaN(principal) || principal <= 0) {
alert("Please enter a valid investment amount.");
return;
}
if (isNaN(rate) || rate < 0) {
alert("Please enter a valid interest rate.");
return;
}
// Calculation Logic: (Principal * Rate * Days) / (365 * 100)
// Note: Ghana T-Bills typically use actual/365 day count convention.
var interest = (principal * rate * days) / 36500;
var totalMaturity = principal + interest;
// Display Results
document.getElementById("displayDuration").innerText = days + " Days";
document.getElementById("displayRate").innerText = rate + "% p.a.";
// Formatting to currency
document.getElementById("interestEarned").innerText = interest.toLocaleString('en-GH', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
document.getElementById("maturityValue").innerText = totalMaturity.toLocaleString('en-GH', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
resultsDiv.style.display = "block";
}
Understanding GCB Treasury Bill Investments
Investing in Government of Ghana Treasury Bills through Ghana Commercial Bank (GCB) is one of the safest ways to grow your capital in the local financial market. This calculator helps investors estimate the returns on their investment based on the current interest rates and the chosen tenor (duration).
How GCB Treasury Bills Work
Treasury Bills (T-Bills) are short-term debt securities issued by the Bank of Ghana (BoG) on behalf of the government to finance expenditure. When you buy a T-Bill through GCB, you are essentially lending money to the government for a specific period. In return, the government pays you interest.
GCB facilitates this process as a primary dealer, allowing customers to purchase T-Bills directly from their bank accounts. The available tenors usually include:
91-Day Bill: A short-term investment maturing in approximately 3 months.
182-Day Bill: A medium-term investment maturing in approximately 6 months.
364-Day Note: A longer-term investment maturing in 1 year.
How to Use This Calculator
To estimate your potential earnings, follow these steps:
Investment Amount (GHS): Enter the amount of Ghana Cedis you wish to invest. GCB typically has a minimum investment threshold (e.g., GHS 100 or GHS 200).
Annual Interest Rate (%): Input the current annual percentage rate. T-Bill rates fluctuate weekly based on the BoG auction. You can check the latest rates on the GCB website or financial news portals.
Tenor: Select the duration of your investment (91, 182, or 364 days).
The Calculation Formula
The interest on Ghana Treasury Bills is calculated using simple interest based on the number of days in the year (typically 365 days). The formula used is:
Interest = (Principal × Rate × Days) / 36500
For example, if you invest GHS 10,000 at a rate of 25% for 91 days:
Interest = (10,000 × 25 × 91) / 36500
Interest ≈ GHS 623.29
Maturity Value ≈ GHS 10,623.29
Why Invest Through GCB?
Risk-Free: T-Bills are backed by the full faith and credit of the Government of Ghana, making them effectively risk-free.
No Withholding Tax: Currently, interest earned on Treasury Bills by individuals is generally exempt from tax in Ghana (verify current tax laws with your banker).
Liquidity: While intended to be held to maturity, T-Bills can be discounted (sold back) before maturity if you urgently need cash, though this may attract a rediscounting fee.
Ease of Rollover: You can instruct GCB to automatically rollover your principal and interest upon maturity, allowing for compounding growth over time.