Annual Leave - How to calculate

How to calculate annual leave entitlement - step by step

UK annual leave entitlement varies by working pattern. Here's how to calculate annual leave days correctly for the most common scenarios your HR team will encounter.


1

Start with the statutory minimum

UK full-time employees are legally entitled to a minimum of 28 days paid annual leave per year under the Working Time Regulations 1998 — including bank holidays. Many employers offer enhanced entitlements above this.

2

Calculate pro-rata for part-time staff

For part-time employees, divide the number of days they work per week by 5, then multiply by the full-time entitlement. The result should always be rounded up to the nearest half-day, never rounded down.

(Days worked per week ÷ 5) × 28 = entitlement
Example: 3 days/week → (3 ÷ 5) × 28 = 16.8 days
3

Adjust for mid-year starters and leavers

For employees who join or leave part-way through the leave year, calculate their monthly accrual rate and multiply by the months worked (or remaining).

Full entitlement ÷ 12 × months remaining
Example: 28 days ÷ 12 × 6 months = 14 days
4

Decide how bank holidays apply

Most UK employers include bank holidays within the 28-day statutory minimum. In this case, check which bank holidays fall on the employee's working days - those are deducted from their entitlement. If your company offers 28 days plus bank holidays, the statutory minimum is still met.


🇬🇧 UK Statutory Entitlement

28 days

minimum paid annual leave for full-time UK employees, including bank holidays

5.6 weeks

the same entitlement expressed as weeks - useful for calculating hourly workers' leave

12.07%

accrual rate for zero-hours and casual workers, based on hours worked

Source: Working Time Regulations 1998 · Updated 2024


💡 Quick rules to remember

  • Always round pro-rata entitlement up - never down
  • Part-time staff must receive proportionally the same entitlement as full-time colleagues
  • Zero-hours workers accrue leave at 12.07% of hours worked
  • Employers can cap holiday pay at the statutory minimum even if enhanced contractual leave is offered
  • Leave can be carried over, but only if contractual policy allows - there is no automatic statutory right to carry over unused holiday (with limited exceptions)
  • Use the WhosOff free calculator to check any scenario quickly - open the tool


Worked examples

Calculate annual leave days for three common scenarios

These real-world examples show how to calculate annual leave days for the working patterns HR teams encounter most often. Use the WhosOff free calculator to check any variation.


🧑‍💼

Full-time employee

Sarah works Monday to Friday (5 days/week) and receives the UK statutory minimum entitlement of 28 days, including bank holidays.

5 ÷ 5 × 28 = 28 days
28
days per year, no further pro-rata needed
👩‍💻

Part-time employee (3 days)

Tom works Monday to Wednesday - 3 days per week. His entitlement is calculated pro-rata against the full-time 28-day minimum.

(3 ÷ 5) × 28 = 16.8 days
16.8
days per year rounded up to 17 - never down
⏰

Hourly worker (20 hrs/week)

Aisha works 20 hours/week. Her company offers 28 days (224 hours for full-time 40hr staff). Her entitlement is calculated in hours.

(20 ÷ 40) × 224 = 112 hours
112
hours per year ideal for shift and zero-hours workers

Need to calculate a different scenario?

The WhosOff free annual leave calculator handles all working patterns - full-time, part-time, mid-year starters, and hourly workers - in both days and hours. Free to use, no account needed.

Open Calculator 📅 Public Holiday Lookup

Annual leave accrual

How to calculate annual leave accrual - monthly rates and the 12.07% rule

Understanding how to calculate leave accrual matters most for new starters, leavers, and zero-hours workers. Here's how holiday leave accrual works in practice, with the formulas you need.


UK statutory minimum entitlements
📅

Work out annual leave accrual by month

For most salaried employees, leave accrues at one-twelfth of the annual entitlement per month. This is the standard way to calculate annual leave accrual for mid-year starters and leavers.

Monthly accrual formula
Annual entitlement ÷ 12
e.g. 28 ÷ 12 = 2.33 days per month

⏱️

12.07% rule for casual and zero-hours workers

Workers with no fixed hours accrue annual leave at a rate of 12.07% of hours worked. This rate is derived from 5.6 weeks' leave as a proportion of the remaining 46.4 working weeks in a year.

Hourly accrual formula
Hours worked × 12.07%
e.g. 100 hours × 12.07% = 12.07 hours of accrued annual leave

🔄

Accrued annual leave on termination

When an employee leaves, any accrued annual leave not yet taken must be paid out at the point of termination. Calculate how much leave has accrued in the final part-year using the monthly formula, subtract any leave already taken, and pay the balance.





About WhosOff

Once you've calculated leave entitlements, WhosOff helps you manage them all year round



🧮

Free annual leave calculator, no sign-up needed

Use the WhosOff free holiday calculator to check entitlements for any working pattern - full-time, part-time, hourly, mid-year. It's a guide to help you get to the right number quickly.


📅

Manage leave requests once entitlements are set

WhosOff is the leave management system that handles everything after you've established entitlements - requests, approvals, shared team calendars, and leave tracking - for teams of all sizes.


🇬🇧

Built around UK leave rules

UK bank holiday calendars, Working Time Regulations statutory minimums, and carry-over policies are all built into WhosOff - so the rules you've calculated stay enforced consistently, every year.


📞

UK-based support, Monday to Friday

Our Canterbury-based team answers calls and emails Monday to Friday, 9am–5.30pm. If you have questions about entitlement calculations or how WhosOff handles specific scenarios, they'll have an answer.


WhosOff at a glance

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in business since 2005
  • Free annual leave calculator - no sign-up
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Manual vs Calculator

Calculating annual leave manually vs using the WhosOff calculator

You can calculate annual leave by hand - but it's easy to make mistakes, especially with part-time pro-rata and mid-year accrual. Here's what the WhosOff calculator handles for you.


Scenario Calculating manually WhosOff calculator
Full-time employee (5 days/week) Straightforward - 28 days statutory ✓ Confirms in seconds, no maths needed
Part-time pro-rata (any pattern) ✗ Formula error-prone, easy to round wrong way ✓ Calculated instantly, always rounds correctly
Mid-year starter ✗ Requires monthly accrual rate + month count ✓ Enter start date, result calculated immediately
Hourly / zero-hours worker ✗ 12.07% formula, easy to misapply ✓ Enter hours worked, entitlement calculated in hours
Results in days and hours ✗ Conversion needed, inconsistent across HR team ✓ Calculate in days or hours - whichever your policy uses
Speed ✗ Minutes per employee, longer for complex cases ✓ Seconds per employee, any pattern

FAQs

Annual leave calculation
questions, answered

Common questions about holiday tracking software and the WhosOff team holiday tracker.


How do you calculate annual leave entitlement in the UK?

Full-time UK employees working 5 days per week are entitled to a minimum of 28 days paid annual leave per year under the Working Time Regulations 1998, including bank holidays. For part-time employees, you calculate pro-rata entitlement using:

(Days worked per week ÷ 5) × 28 = annual leave entitlement

For example, an employee working 3 days per week receives (3 ÷ 5) × 28 = 16.8 days. Always round up to the nearest half-day - never round down. Use the WhosOff free annual leave calculator to check quickly for any working pattern.

How do you calculate annual leave accrual for a new starter?

To calculate annual leave accrual for a mid-year starter, divide the full annual entitlement by 12 to find the monthly accrual rate, then multiply by the number of months remaining in the leave year from their start date.

Annual entitlement ÷ 12 × months remaining = pro-rata entitlement

For example, if the leave year runs April to March and an employee joins in October (6 months remaining), with a 28-day entitlement: 28 ÷ 12 × 6 = 14 days.

What is annual leave accrual and when does it apply?
Annual leave accrual is the process by which an employee builds up holiday entitlement over time, rather than receiving their full annual allowance on the first day of the leave year. It most commonly applies to new starters during a probation period (some employers only allow accrued leave to be taken rather than the full-year entitlement immediately), or to casual, zero-hours, and variable-hours workers whose leave accrues based on hours worked. For the latter, holiday leave accrual is typically calculated at 12.07% of hours worked.
What is the 12.07% holiday leave accrual rate and how do you calculate it?

The 12.07% accrual rate is used to calculate annual leave for workers with no fixed hours - such as zero-hours, casual, or seasonal staff. It represents 5.6 weeks' leave as a proportion of the 46.4 remaining working weeks in a year (52 − 5.6 = 46.4, and 5.6 ÷ 46.4 = 12.07%).

Hours worked × 12.07% = accrued annual leave (in hours)

For example: 100 hours worked × 12.07% = 12.07 hours of accrued leave. Note that since April 2024, case law developments have affected how irregular-hours workers' holiday pay should be calculated — always seek up-to-date legal advice for complex cases.

How do you work out annual leave accrual when an employee leaves?
When an employee leaves part-way through the leave year, calculate how much leave they have accrued up to their last day (using the monthly accrual formula), then subtract any leave they have already taken. If they have unused accrued leave, this must be paid out at the point of termination. If they have taken more leave than they have accrued, the employer may be able to deduct this from the final pay - if the employment contract allows it.
Are bank holidays included in the 28-day UK statutory entitlement?
It depends on the employer's policy. The most common approach is to include bank holidays within the 28-day statutory minimum — so an employee with 28 days' entitlement who works Monday to Friday would have 8 bank holiday days counted within that 28, leaving 20 days to book freely. Some employers offer 28 days plus bank holidays (or 20 + 8). Both approaches satisfy the statutory minimum. For part-time employees, only bank holidays that fall on their working days are deducted from their entitlement.
How do you calculate annual leave for a part-time employee who works different hours each day?

For employees with irregular daily hours, it's usually clearest to calculate leave in hours rather than days - this avoids disputes about whether a "day" means 4 hours or 8 hours. Establish the full-time hourly equivalent (e.g. 5 days × 8 hours = 40 hours/week × 5.6 weeks = 224 hours annual entitlement), then apply the pro-rata fraction based on the employee's contracted weekly hours.

(Employee's contracted hours/week ÷ full-time hours/week) × full-time entitlement in hours

The WhosOff calculator handles hourly calculations directly - select "calculate in hours" when using the tool.

Can annual leave be carried over to the next leave year?
There is no automatic statutory right for employees to carry over unused annual leave, with two exceptions: leave that couldn't be taken due to statutory leave (maternity, paternity, sick leave) may carry over; and since April 2024, workers who were prevented from taking statutory leave due to their employer may carry up to 4 weeks forward. Beyond these exceptions, carry-over depends entirely on the employer's contractual policy. Many employers allow a set number of days (commonly 5) to be carried forward as an incentive — but the terms must be clearly set out in the contract.
Is the WhosOff annual leave calculator free to use?
Yes - the WhosOff annual leave calculator is completely free to use, with no account or sign-up required. It handles full-time, part-time, mid-year, and hourly calculations, in both days and hours. The calculator is provided as a guide - we always recommend verifying the output against your own contractual and statutory obligations.
What is the difference between annual leave entitlement and accrued annual leave?
Annual leave entitlement is the total amount of paid holiday an employee is entitled to over a full leave year. Accrued annual leave is the portion of that entitlement that has built up so far during the current leave year - based on the time worked since the start of the leave year or the employee's start date. For example, a full-year entitlement of 28 days with 6 months elapsed means 14 days of accrued annual leave, regardless of how many days have actually been taken.

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