.pro-rata-calc-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
color: #333;
line-height: 1.6;
}
.calc-container {
background-color: #ffffff;
border: 1px solid #e2e8f0;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.form-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.form-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
font-size: 14px;
color: #4a5568;
}
.input-group input {
width: 100%;
padding: 12px;
border: 1px solid #cbd5e0;
border-radius: 6px;
font-size: 16px;
transition: border-color 0.2s;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #3182ce;
outline: none;
box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.1);
}
.calc-btn {
display: block;
width: 100%;
background-color: #3182ce;
color: white;
padding: 15px;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: 700;
cursor: pointer;
margin-top: 10px;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #2b6cb0;
}
.result-box {
background-color: #f7fafc;
border: 1px solid #edf2f7;
border-radius: 8px;
padding: 25px;
margin-top: 30px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
align-items: center;
padding: 12px 0;
border-bottom: 1px solid #e2e8f0;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
font-weight: 600;
color: #4a5568;
}
.result-value {
font-weight: 700;
font-size: 18px;
color: #2d3748;
}
.highlight-value {
color: #38a169;
font-size: 22px;
}
.article-content h2 {
color: #2d3748;
margin-top: 30px;
margin-bottom: 15px;
}
.article-content p {
margin-bottom: 15px;
color: #4a5568;
}
.article-content ul {
margin-bottom: 15px;
padding-left: 20px;
}
.article-content li {
margin-bottom: 8px;
color: #4a5568;
}
.help-text {
font-size: 12px;
color: #718096;
margin-top: 5px;
}
Understanding the Pro Rata Hourly Rate
Calculating your pro rata salary or hourly rate is essential when moving from full-time to part-time work, or when comparing job offers with different working hours. "Pro rata" is a Latin term meaning "in proportion," and in the context of employment, it refers to pay that is calculated proportionately to the hours worked relative to a standard full-time schedule.
How is Hourly Rate Calculated?
To determine your hourly rate from an annual salary, the calculator uses the following logic:
- Total Annual Hours: Multiplies the standard full-time weekly hours by the number of weeks in a year (typically 52).
- Hourly Rate: Divides the Full-Time Annual Salary by the Total Annual Hours.
For example, if a full-time role pays $52,000 a year for a 40-hour week:
$52,000 ÷ (40 hours × 52 weeks) = $25.00 per hour.
Calculating Pro Rata Salary
Once the hourly rate is established, calculating your specific pro rata salary involves multiplying that hourly rate by your actual contracted hours. This figure represents what you will actually earn based on your part-time schedule.
Formula: (Hourly Rate) × (Your Weekly Hours) × (Weeks Per Year)
Why Weeks Per Year Matters
While most simple calculations use 52 weeks, a year is actually 365 days (or 366 in a leap year). 365 days divided by 7 days a week equals approximately 52.143 weeks. Some payroll departments use 52.143 or even 260/261 working days for higher precision. This calculator allows you to adjust the "Weeks Per Year" field if your employer uses a specific payroll divisor.
Common Use Cases
- Part-Time Negotiations: Understanding exactly how a reduction in hours impacts your take-home pay.
- Freelance Comparisons: converting a salaried offer into an hourly rate to compare against freelance contracting rates.
- Job Sharing: Determining the fair split of a salary between two employees sharing one full-time role.
function calculateHourlyProRata() {
// Get inputs
var ftSalary = document.getElementById('fullTimeSalary').value;
var stdHours = document.getElementById('standardHours').value;
var myHours = document.getElementById('myHours').value;
var weeks = document.getElementById('weeksPerYear').value;
// Basic Validation
if (ftSalary === "" || stdHours === "" || myHours === "" || weeks === "") {
alert("Please fill in all fields to calculate rates.");
return;
}
var salaryNum = parseFloat(ftSalary);
var stdHoursNum = parseFloat(stdHours);
var myHoursNum = parseFloat(myHours);
var weeksNum = parseFloat(weeks);
if (isNaN(salaryNum) || isNaN(stdHoursNum) || isNaN(myHoursNum) || isNaN(weeksNum)) {
alert("Please enter valid numbers.");
return;
}
if (stdHoursNum <= 0 || weeksNum <= 0) {
alert("Hours and Weeks must be greater than zero.");
return;
}
// Calculation Logic
// 1. Calculate Hourly Rate based on full time stats
var totalFtHoursPerYear = stdHoursNum * weeksNum;
var hourlyRate = salaryNum / totalFtHoursPerYear;
// 2. Calculate Pro Rata Annual Salary based on my hours
var proRataAnnual = hourlyRate * myHoursNum * weeksNum;
// 3. Breakdowns
var monthlyPay = proRataAnnual / 12;
var weeklyPay = proRataAnnual / weeksNum;
// Formatting currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
});
// Update DOM
document.getElementById('dispHourlyRate').innerText = formatter.format(hourlyRate);
document.getElementById('dispAnnual').innerText = formatter.format(proRataAnnual);
document.getElementById('dispMonthly').innerText = formatter.format(monthlyPay);
document.getElementById('dispWeekly').innerText = formatter.format(weeklyPay);
// Show result box
document.getElementById('resultBox').style.display = 'block';
}