Total vacation days a full-time employee gets in a full year.
Standard Year (365 days)
Leap Year (366 days)
Total Days Employed:0
Percentage of Year Worked:0%
Exact Entitlement:0
Pro Rata Leave Due:0 Days
function calculateProRataLeave() {
// Get DOM elements
var entitlementInput = document.getElementById("fullYearEntitlement");
var startDateInput = document.getElementById("calcStartDate");
var endDateInput = document.getElementById("calcEndDate");
var yearBasisInput = document.getElementById("daysInYear");
var errorDiv = document.getElementById("calcError");
var resultDiv = document.getElementById("calcResult");
// Get Values
var entitlement = parseFloat(entitlementInput.value);
var startStr = startDateInput.value;
var endStr = endDateInput.value;
var basis = parseInt(yearBasisInput.value);
// Reset display
errorDiv.style.display = "none";
resultDiv.style.display = "none";
// Validations
if (isNaN(entitlement) || entitlement < 0) {
errorDiv.innerText = "Please enter a valid number for Annual Entitlement.";
errorDiv.style.display = "block";
return;
}
if (!startStr || !endStr) {
errorDiv.innerText = "Please select both start and end dates.";
errorDiv.style.display = "block";
return;
}
var startDate = new Date(startStr);
var endDate = new Date(endStr);
// Validate dates order
if (endDate < startDate) {
errorDiv.innerText = "End date cannot be before Start date.";
errorDiv.style.display = "block";
return;
}
// Calculate difference in time
var timeDiff = endDate.getTime() – startDate.getTime();
// Calculate days difference (Divide by milliseconds in a day)
// We add 1 to include the start date as a working day
var daysWorked = (timeDiff / (1000 * 3600 * 24)) + 1;
daysWorked = Math.round(daysWorked); // Handle daylight saving adjustments
// Logic: (Days Worked / Days in Year) * Annual Entitlement
var percentage = (daysWorked / basis);
var exactLeave = percentage * entitlement;
// Rounding to 2 decimals for display
var exactLeaveRounded = Math.round(exactLeave * 100) / 100;
var percentageDisplay = Math.round(percentage * 10000) / 100; // Display % with 2 decimals
// Update DOM
document.getElementById("resDaysWorked").innerText = daysWorked + " days";
document.getElementById("resPercentage").innerText = percentageDisplay + "%";
document.getElementById("resExact").innerText = exactLeaveRounded + " days";
document.getElementById("resFinal").innerText = exactLeaveRounded + " Days";
resultDiv.style.display = "block";
}
How to Calculate Leaves on Pro Rata Basis: A Complete Guide
Calculating leave entitlement on a pro rata basis is a fundamental task for HR professionals, business owners, and employees starting or leaving a job partway through the year. "Pro rata" essentially means "in proportion." When an employee does not work a full year, they are not entitled to the full annual leave allowance; instead, they receive a portion relative to the time they worked.
Why is Pro Rata Calculation Necessary?
Most employment contracts stipulate an annual leave entitlement (e.g., 20 days or 28 days per year). However, this figure assumes the employee works for the entire 12-month leave year. Adjustments are required in the following scenarios:
New Starters: An employee joins the company in June, but the leave year runs from January to December.
Leavers: An employee resigns and their last working day is in August.
Part-time Shifts: An employee reduces their working days from 5 days a week to 3 days a week.
The Pro Rata Formula
The standard mathematical approach to calculating pro rata holiday entitlement is fairly straightforward. It ensures fairness by correlating the benefit strictly to the time served.
The Formula:
(Days Employed ÷ Days in Year) × Full Annual Entitlement = Pro Rata Leave
Step-by-Step Calculation:
Determine Full Annual Entitlement: This is the total number of days an employee would get if they worked the full year (e.g., 25 days).
Calculate Days Employed: Count the number of calendar days between the start date and end date (inclusive).
Divide by Year Length: Divide the days employed by 365 (or 366 in a leap year) to get the "accrual factor."
Multiply by Entitlement: Multiply the accrual factor by the full annual entitlement.
Practical Examples
Example 1: The New Starter
Sarah joins a company on July 1st. The company's leave year runs from January 1st to December 31st. The standard holiday allowance is 20 days.
Period Worked: July 1st to December 31st = 184 days.
Calculation: (184 ÷ 365) × 20
Result: 0.504 × 20 = 10.08 days
Note: Most companies will round this up to 10.5 days or 10 days depending on company policy.
Example 2: The Leaver
John is leaving his job. His last day is March 31st. He has an annual entitlement of 25 days.
Period Worked: January 1st to March 31st = 90 days.
Calculation: (90 ÷ 365) × 25
Result: 0.246 × 25 = 6.16 days
John is entitled to roughly 6 days of leave. If he has already taken 10 days of vacation in January, he owes the company 4 days' worth of salary back.
Handling Rounding and Public Holidays
Calculators often produce decimal results (e.g., 12.33 days). Employment law in many jurisdictions (like the UK) states that you cannot round down statutory leave entitlement, but you can round up. Consequently, 12.33 is often treated as 12.5 or 13 days in the employee's favor to ensure compliance.
Public Holidays
Ensure you know if the "Annual Entitlement" figure includes public holidays. If an employee's contract states "20 days plus bank holidays," calculate the pro rata for the 20 days first, and then add the specific bank holidays that fall within their employment period.
Using the Calculator
Our tool above simplifies this process. By inputting your start and end dates along with your contract's full-year allowance, it automatically determines the exact number of days you have accrued. This helps prevent disputes over final paychecks and ensures transparency between HR and staff.