Annual Leave Calculator
Free, instant estimate — no sign-up. Enter the details below to see the calculation and the result.
Calculate your estimate
Informational estimate only, based on official GOV.UK guidance and assumes the person is eligible — see the eligibility notes below. Not legal or payroll advice.
Quick answer: Annual leave accrues pro-rata through the leave year — full entitlement (days per week × 5.6) multiplied by the proportion of the leave year worked so far.
Written by Ruby Miller · HR & Employment Law Content Lead
How this is calculated
This calculator pro-rates the full annual leave entitlement (days worked per week × 5.6, capped at 28 days) by how many weeks of the current leave year have been worked so far — useful for checking accrued leave partway through the year, such as for a new starter or someone leaving mid-year.
The arithmetic is simple, but the two numbers that go into it — the full-year entitlement and the leave year itself — are where most confusion actually happens. The full entitlement comes from regulation 13 and 13A of the Working Time Regulations 1998; the “weeks employed” figure needs to be measured against your specific employer’s leave year, which defaults to your employment anniversary date if your contract doesn’t set one explicitly.
Not sure what your full-year entitlement should be before pro-rating it? Start with the Holiday Entitlement Calculator to confirm the statutory minimum for your working pattern.
Accrual at different points in the leave year
For a standard 5-day, 28-day-entitlement pattern, here’s roughly how much leave has typically built up by different points in the year:
| Weeks employed | Proportion of year | Leave accrued |
|---|---|---|
| 13 weeks | 25% | 7.0 days |
| 26 weeks | 50% | 14.0 days |
| 39 weeks | 75% | 21.0 days |
| 52 weeks | 100% | 28.0 days |
A part-time worker on a different pattern accrues on exactly the same curve, just against their own full-year figure — someone on 3 days a week (16.8 days full entitlement) is at 8.4 days accrued at the halfway point, not 14.
Who this applies to
Eligibility is assumed, not verified. What actually needs to be true:
- Worker or employee status under UK employment law.
- A defined “leave year” start date — either set by the employer, or defaulting to the employment start date if not specified.
Special cases
Changing hours partway through the year
If your days-per-week pattern changed during the leave year, calculate each period separately using the days worked during that period, then add the two pro-rata figures together — this calculator handles one consistent pattern at a time.
Periods of unpaid leave
Unpaid leave (such as unpaid parental leave or a career break) can affect how much statutory holiday accrues during that period — check whether the weeks in question should count as “weeks employed” for this calculation.
TUPE transfers
If your employment transferred to a new employer under TUPE, your continuous service and accrued leave normally carry over from the old employer — the “weeks employed” figure should reflect total service, not just time with the new employer.
Worked examples
What this calculator doesn’t cover
- Assumes a standard 52-week leave year rather than a custom or short first/final leave year.
- Does not handle leave carry-over from a previous leave year.
- Does not account for any additional contractual leave on top of the statutory minimum.
- Does not subtract leave already taken — it gives total accrued, not remaining balance.
The bit people get wrong doing this by hand
Most of the “my payslip doesn’t match your calculator” emails we get trace back to one of these three, not to an actual error in the maths.
- ✕Confusing “accrued” with “remaining.” This is the one that catches nearly everyone at least once. This figure is total leave built up so far — if 5 days have already been taken, the actual remaining balance is the accrued figure minus those 5 days, not the accrued figure itself.
- ✕Using the calendar year instead of the leave year. A leave year that runs April to March will give a very different “weeks employed” count in, say, November than a leave year running January to December — always check which one your contract or handbook actually uses.
- ✕Forgetting that the full-year figure changes with the working pattern. 50% of the year worked is not automatically 14 days — it’s 50% of that specific person’s full entitlement, which depends on their own days-per-week.
FAQs
What if my leave year isn’t a standard 52 weeks?
This calculator assumes a standard 52-week leave year. If your first or last leave year is shorter, the pro-rata figure should be adjusted accordingly.
Can I carry over unused leave to the next leave year?
Some carry-over is allowed in specific circumstances (such as long-term sickness or certain family leave), but this calculator does not model carry-over — check your employer’s policy.
How do I know how many weeks I’ve actually been employed this leave year?
Count from the start of your employer’s current leave year (not your start date, unless those happen to be the same) up to today or your leaving date, in whole weeks. If your leave year isn’t published anywhere, ask HR — it’s a required piece of information, not a formality.
Does this figure include leave I’ve already taken?
No — this is the total leave accrued to date, not your remaining balance. Subtract any days already taken to get what’s actually left to book or be paid out.
My employer says I’ve accrued less than this calculator shows. What could explain that?
Common reasons include a different leave-year start date than assumed, unpaid leave periods that don’t count as “weeks employed,” or a genuine payroll error — ask for the specific calculation your employer used so you can compare it line by line against this one.
Is accrued leave paid out if I’m made redundant partway through the year?
Yes — any statutory holiday accrued but not taken by the leaving date is normally paid out as part of your final pay. Use this calculator to check the accrued figure, then the Holiday Pay Calculator to value each day of it.
Does sick leave or maternity leave pause my accrual?
No. Statutory holiday continues to accrue as normal throughout sickness absence and all forms of statutory family leave — those weeks still count towards the “weeks employed” figure for this calculation.