What is Pro Rata?
"Pro rata" is a Latin term meaning "in proportion." In finance and business, it refers to allocating a quantity or cost proportionally. This is commonly used when an event occurs mid-period, and an amount needs to be divided based on the time elapsed or the portion of service used. For example, if a subscription costs $1200 for 30 days, and you cancel after 15 days, the pro rata refund would be based on the unused portion of the service.
The formula used is:
Pro Rata Share = (Total Amount / Total Period) * Partial Period
This calculation ensures fairness by distributing costs or benefits according to usage or time.
Example Calculation:
Imagine you have a project that costs $1200 for a total of 30 days of work. If only 15 days of work were completed, the pro rata cost for those 15 days would be calculated as follows:
Pro Rata Share = ($1200 / 30 days) * 15 days
Pro Rata Share = $40/day * 15 days
Pro Rata Share = $600
This means that for the 15 days of work completed, the cost is $600.
function calculateProRata() {
var totalAmount = parseFloat(document.getElementById("totalAmount").value);
var totalPeriod = parseFloat(document.getElementById("totalPeriod").value);
var partialPeriod = parseFloat(document.getElementById("partialPeriod").value);
var resultDiv = document.getElementById("proRataResult");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(totalAmount) || isNaN(totalPeriod) || isNaN(partialPeriod)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (totalPeriod <= 0) {
resultDiv.innerHTML = "Total Period/Quantity must be greater than zero.";
return;
}
var proRataShare = (totalAmount / totalPeriod) * partialPeriod;
// Displaying the result with appropriate units based on the example context
resultDiv.innerHTML =
"The Pro Rata Share is:
" + proRataShare.toFixed(2) + "";
}
.pro-rata-calculator {
font-family: sans-serif;
max-width: 700px;
margin: 20px auto;
padding: 20px;
border: 1px solid #ccc;
border-radius: 8px;
background-color: #f9f9f9;
}
.pro-rata-calculator h2 {
text-align: center;
color: #333;
margin-bottom: 15px;
}
.calculator-inputs, .calculator-result, .calculator-explanation {
margin-bottom: 20px;
padding: 15px;
background-color: #fff;
border: 1px solid #eee;
border-radius: 5px;
}
.input-group {
margin-bottom: 15px;
display: flex;
align-items: center;
}
.input-group label {
flex: 1;
margin-right: 10px;
font-weight: bold;
color: #555;
}
.input-group input[type="number"] {
flex: 2;
padding: 8px;
border: 1px solid #ccc;
border-radius: 4px;
box-sizing: border-box; /* Ensures padding doesn't affect width */
}
.pro-rata-calculator button {
display: block;
width: 100%;
padding: 10px;
background-color: #007bff;
color: white;
border: none;
border-radius: 5px;
font-size: 16px;
cursor: pointer;
transition: background-color 0.3s ease;
}
.pro-rata-calculator button:hover {
background-color: #0056b3;
}
.calculator-result p {
font-size: 1.1em;
text-align: center;
color: #28a745;
}
.calculator-explanation h3, .calculator-explanation h4 {
color: #333;
margin-bottom: 10px;
}
.calculator-explanation p {
line-height: 1.6;
color: #444;
}
.calculator-explanation strong {
color: #000;
}