*NPV > 0 indicates a financially viable project. A BCR > 1.0 suggests benefits outweigh costs.
function calculateCBA() {
// Get input values
var initialOutlay = parseFloat(document.getElementById('initialOutlay').value);
var annualBenefit = parseFloat(document.getElementById('annualBenefit').value);
var annualCost = parseFloat(document.getElementById('annualCost').value);
var discountRate = parseFloat(document.getElementById('discountRate').value);
var timeHorizon = parseInt(document.getElementById('timeHorizon').value);
// Validation
if (isNaN(initialOutlay) || isNaN(annualBenefit) || isNaN(annualCost) || isNaN(discountRate) || isNaN(timeHorizon)) {
alert("Please enter valid numerical values for all fields.");
return;
}
if (timeHorizon <= 0) {
alert("Time horizon must be at least 1 year.");
return;
}
var rate = discountRate / 100;
var totalPVBenefits = 0;
// Initial outlay occurs at t=0, so its PV is the value itself.
// We accumulate subsequent annual costs below.
var totalPVCosts = initialOutlay;
// Loop through each year to calculate PV
for (var t = 1; t 0 ? (totalPVBenefits / totalPVCosts) : 0;
var roi = totalPVCosts > 0 ? ((npv / totalPVCosts) * 100) : 0;
// Formatting currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
// Display Results
document.getElementById('npvResult').innerText = formatter.format(npv);
document.getElementById('bcrResult').innerText = bcr.toFixed(2) + " : 1″;
document.getElementById('roiResult').innerText = roi.toFixed(2) + "%";
document.getElementById('pvBenefitsResult').innerText = formatter.format(totalPVBenefits);
document.getElementById('pvCostsResult').innerText = formatter.format(totalPVCosts);
// Show result container
document.getElementById('cbaResults').style.display = 'block';
}
Understanding Cost-Benefit Analysis (CBA) Rates
A CBA Rates Calculator is a financial modeling tool used to evaluate the economic feasibility of a project or investment decision. Unlike a simple loan or mortgage calculator, a Cost-Benefit Analysis (CBA) assesses the "Net Present Value" of future cash flows by applying a specific Discount Rate. This rate adjusts future sums to reflect their value in today's dollars, accounting for inflation, opportunity cost, and risk.
Key Metrics Explained
1. Discount Rate
The discount rate is the percentage used to convert future costs and benefits into present-day value. A higher discount rate implies that money available today is worth much more than money in the future (high time preference or risk). In public sector projects, this rate is often set by government policy (e.g., 3-7%), while private sector projects might use the company's weighted average cost of capital (WACC).
2. Net Present Value (NPV)
NPV is the sum of all present values of benefits minus the sum of all present values of costs.
Formula:NPV = Σ PV(Benefits) – Σ PV(Costs)
If the result is positive (Green), the project is expected to generate value. If negative, the costs outweigh the benefits given the chosen discount rate.
3. Benefit-Cost Ratio (BCR)
The BCR is a ratio indicator used to summarize the overall value for money of a project.
Formula:BCR = Total PV Benefits / Total PV Costs
A BCR greater than 1.0 is generally expected for a project to proceed, as it indicates that for every dollar spent, more than one dollar in value is generated.
How to Use This Calculator
This tool is designed for project managers, business analysts, and financial planners. To perform a basic analysis:
Initial Investment: Enter the upfront capital required to start the project (t=0).
Annual Benefit: Estimate the yearly revenue or savings generated by the project.
Annual Cost: Estimate the recurring maintenance or operating costs.
Discount Rate: Enter your required rate of return or hurdle rate (e.g., 5% or 10%).
Time Horizon: Specify how many years the project will run.
The calculator will automatically discount the future cash flows for every year in your time horizon and compare them against the total costs to provide your viability metrics.