The total days a full-time employee receives per year (including bank holidays).
Standard hours worked by a full-time employee (e.g., 37.5 or 40).
The number of hours you work per week.
Enter 12 for a full year. Enter less if starting/leaving mid-year.
Please enter valid positive numbers for all fields.
Pro Rata Percentage:0%
Annual Entitlement (Days):0
Annual Entitlement (Hours):0
functioncalculateLeave = function() { // Fallback definition if var logic used below
};
function calculateLeave() {
// Retrieve inputs
var ftEntitlement = parseFloat(document.getElementById('fullTimeEntitlement').value);
var ftHours = parseFloat(document.getElementById('fullTimeHours').value);
var ptHours = parseFloat(document.getElementById('partTimeHours').value);
var months = parseFloat(document.getElementById('monthsEmployed').value);
var errorMsg = document.getElementById('error-message');
var resultContainer = document.getElementById('result-container');
// Validation
if (isNaN(ftEntitlement) || isNaN(ftHours) || isNaN(ptHours) || isNaN(months) || ftHours <= 0 || months confusing.
// Simpler Hour Formula: (ftEntitlement * (ftHours/5)) is total FT hours usually?
// Let's use: (Final Days / ftEntitlement) * (ftEntitlement in Hours)
// Standard approach: Final Days * (ptHours / DaysWorkedPerWeek).
// Since we don't ask for days worked per week, we calculate strict hour entitlement:
// (ftEntitlement days * (ftHours / 5)) * ratio * durationRatio?
// Simplest accurate metric: (Final Days) * (ptHours / 5). Assumes 5 day standard week basis for the entitlement figure.
// Alternative Hours Calculation:
// If 28 days is the entitlement for 40 hours.
// Ratio is 0.5 (20 hours).
// Entitlement is 14 days.
// 14 days @ (20/5 = 4 hours per day) = 56 hours.
var hoursPerDay = ptHours / 5; // Assuming standard 5 day spread for calculation basis
var finalHours = finalDays * hoursPerDay;
// Update UI
resultContainer.style.display = 'block';
document.getElementById('res-percentage').innerHTML = (ratio * 100).toFixed(1) + "%";
document.getElementById('res-days').innerHTML = finalDays.toFixed(2) + " Days";
document.getElementById('res-hours').innerHTML = finalHours.toFixed(1) + " Hours";
}
How Do You Calculate Pro Rata Annual Leave?
Calculating pro rata annual leave is an essential task for employers and HR managers handling part-time staff, as well as for employees ensuring they are receiving their fair statutory entitlement. "Pro rata" literally means "in proportion," meaning your holiday entitlement should be directly proportional to the amount of time you work compared to a full-time employee.
In most jurisdictions, part-time workers are legally entitled to the same holiday treatment as full-time workers, calculated on a pro-rata basis. This ensures that a person working half a week gets exactly half the holiday allowance of someone working a full week.
The Pro Rata Formula
The calculation generally involves determining the proportion of hours a part-time employee works compared to a standard full-time week, and applying that percentage to the full annual leave allowance.
(Hours Worked ÷ Full-Time Hours) × Full-Time Annual Leave = Pro Rata Leave
If the employee starts or leaves partway through the leave year, you must effectively perform a double calculation: first for the part-time status, and second for the portion of the year they were employed.
Imagine an employee works 3 days a week (22.5 hours) where full-time is 37.5 hours. They get 28 days full entitlement, but they only started 3 months ago.
Step 1 (Hours Ratio): 22.5 ÷ 37.5 = 0.6
Step 2 (Annual Pro Rata): 0.6 × 28 = 16.8 days (full year equivalent)
Step 3 (Time Ratio): 3 months ÷ 12 months = 0.25
Final Calculation: 16.8 × 0.25 = 4.2 days accrued.
Why calculate in hours vs. days?
While many contracts state leave in "days," calculating in hours is often more accurate for shift workers or employees who work irregular hours. If an employee works different hours on different days (e.g., 4 hours on Monday, 8 hours on Tuesday), taking "one day" of leave deducts a different amount of time depending on the day. In these cases, converting the total annual entitlement into an "hour bank" is the safest way to track leave.
Statutory Minimums
Always ensure the result meets the statutory minimum for your country. For example, in the UK, the statutory minimum is 5.6 weeks (capped at 28 days). A calculator provides a mathematical guideline, but specific employment contracts may offer more generous terms than the statutory minimum.