The total days a full-time employee receives per year.
Enter the date the employee leaves or the end of the leave year.
Please enter valid dates and entitlement figures. End date must be after start date.
Days Employed:0
Percentage of Year:0%
Exact Entitlement:0 days
Rounded Entitlement (to nearest 0.5):0 days
function calculateLeave() {
// Get inputs
var fullEntitlement = parseFloat(document.getElementById('fullEntitlement').value);
var startDateStr = document.getElementById('startDate').value;
var endDateStr = document.getElementById('endDate').value;
var resultBox = document.getElementById('resultBox');
var errorMsg = document.getElementById('errorMsg');
// Reset display
resultBox.style.display = 'none';
errorMsg.style.display = 'none';
// Validation
if (isNaN(fullEntitlement) || !startDateStr || !endDateStr) {
errorMsg.style.display = 'block';
errorMsg.innerHTML = "Please fill in all fields correctly.";
return;
}
var startDate = new Date(startDateStr);
var endDate = new Date(endDateStr);
// Check valid date range
if (endDate 100) {
percentage = 100;
daysEmployed = daysInYear;
}
// Calculate entitlement
var exactEntitlement = (daysEmployed / daysInYear) * fullEntitlement;
// Rounding logic: Round to nearest 0.5 usually, or standard 1 decimal
var roundedEntitlement = Math.round(exactEntitlement * 2) / 2;
// Display results
document.getElementById('displayDays').innerText = daysEmployed + " days";
document.getElementById('displayPercent').innerText = percentage.toFixed(2) + "%";
document.getElementById('displayExact').innerText = exactEntitlement.toFixed(4) + " days";
document.getElementById('displayRounded').innerText = roundedEntitlement.toFixed(1) + " days";
resultBox.style.display = 'block';
}
How Pro Rata Annual Leave Works
Calculating annual leave entitlements for employees who start or leave part-way through a year, or who work part-time, is a critical task for HR departments and business owners. This "pro rata" (in proportion) calculation ensures fairness and compliance with labor laws.
When to Use This Calculator
This tool is designed for scenarios where an employee's employment period does not cover the full annual leave year. Common situations include:
New Starters: An employee joins the company in the middle of the leave year.
Leavers: An employee resigns or is terminated before the end of the leave year.
Fixed-Term Contracts: Staff hired for a specific project duration shorter than 12 months.
The Pro Rata Formula
The standard method for calculating pro rata holiday entitlement involves determining the percentage of the year the employee has worked. The basic formula used by this calculator is:
(Days Employed / 365) × Full Annual Entitlement = Pro Rata Entitlement
For example, if a full-time employee is entitled to 28 days of holiday per year, but they only work for the first 182 days of the year:
(182 / 365) × 28 = 13.96 days
Most employers will round this figure up to the nearest half-day or full day to simplify booking time off, resulting in 14 days of leave.
Important Considerations
While the math is straightforward, there are several factors to keep in mind:
Inclusive Dates: This calculator treats the end date as a working day (inclusive). If someone leaves on the 31st, that day counts toward their accrual.
Rounding Policies: Statutory guidance often suggests that you cannot round down statutory leave entitlements, but you can round up. Always check local labor laws regarding rounding fractions of days.
Public Holidays: Ensure your "Full Annual Entitlement" figure includes or excludes public holidays as per your company contract. In the UK, for example, the statutory minimum of 28 days can include the 8 bank holidays.
Leap Years: While this calculator uses the standard 365-day divisor, some contracts specify 366 days during a leap year. The difference is usually negligible (fractions of an hour) but worth noting for strict compliance.
Part-Time Workers
If you are calculating leave for someone who works the full year but fewer hours per week (e.g., 3 days a week instead of 5), the calculation is simpler. You generally multiply their full-time equivalent entitlement by the fraction of the week they work. For example, if the full entitlement is 28 days and they work 3 days a week: 28 × (3/5) = 16.8 days.