Calculate your annual leave entitlement based on UK employment law
Standard UK minimum is 28 days (including bank holidays).
Enter the number of days you work in a standard week.
Use 12 for a full year, or less if you started/left mid-year.
Your Estimated Entitlement:
Understanding Pro Rata Holiday in the UK
In the UK, almost all workers are legally entitled to 5.6 weeks of paid holiday per year (known as statutory leave entitlement). This applies to agency workers, workers on zero-hours contracts, and part-time workers.
How the Calculation Works
The term "pro rata" simply means "in proportion." If a full-time employee working 5 days a week is entitled to 28 days of holiday, a part-time employee is entitled to a proportional amount based on the days or hours they work.
The Core Formula: (Annual Entitlement ÷ Full-time Days) × Days Worked Per Week = Pro Rata Entitlement
Example Calculation
If a full-time worker at your company gets 30 days of holiday (including bank holidays) and you work 3 days a week:
Full-time entitlement: 30 days
Divide by full-time week (5 days): 30 ÷ 5 = 6 days per "work day" unit.
Multiply by your days (3): 6 × 3 = 18 days.
What About Bank Holidays?
In the UK, there are usually 8 bank holidays a year. Employers can choose to include these in your statutory 28 days or offer them in addition. For part-time workers, bank holiday entitlement must also be pro-rated. This ensures that a worker whose shift falls on a Monday doesn't get more time off than someone whose shift falls on a Tuesday, simply because most bank holidays land on Mondays.
Important Legal Notes
The statutory minimum is 28 days (including bank holidays) for 5-day-a-week workers.
An employer cannot give you less than the statutory 5.6 weeks equivalent.
Holiday entitlement starts accruing as soon as you start work.
If you leave a job part-way through a year, you are entitled to be paid for any holiday you have accrued but not taken.
function calculateProRataHoliday() {
var fullEntitlement = parseFloat(document.getElementById('fullTimeEntitlement').value);
var daysPerWeek = parseFloat(document.getElementById('daysPerWeek').value);
var monthsWorked = parseFloat(document.getElementById('monthsWorked').value);
// Validation
if (isNaN(fullEntitlement) || isNaN(daysPerWeek) || isNaN(monthsWorked)) {
alert("Please enter valid numbers in all fields.");
return;
}
if (daysPerWeek > 7) {
alert("Days worked per week cannot exceed 7.");
return;
}
if (monthsWorked > 12 || monthsWorked <= 0) {
alert("Months worked must be between 1 and 12.");
return;
}
// Calculation Logic
// Step 1: Calculate the daily multiplier (usually based on a 5-day week)
var dailyMultiplier = fullEntitlement / 5;
// Step 2: Apply days worked per week
var annualProRata = dailyMultiplier * daysPerWeek;
// Step 3: Adjust for part-year (starters/leavers)
var finalEntitlement = annualProRata * (monthsWorked / 12);
// Rounding – UK employers usually round UP to the nearest half day if they round at all
// We will show to 1 decimal place for accuracy
var resultValue = finalEntitlement.toFixed(1);
// Update UI
document.getElementById('holidayResultBox').style.display = 'block';
document.getElementById('holidayResultValue').innerHTML = resultValue + " Days";
var explanation = "Based on a full-time entitlement of " + fullEntitlement + " days, working " + daysPerWeek + " days per week";
if (monthsWorked < 12) {
explanation += " for " + monthsWorked + " months of the year.";
} else {
explanation += " for the full year.";
}
document.getElementById('holidayExplanation').innerHTML = explanation;
}