How UK statutory holiday entitlement is calculated
Almost every UK worker is entitled to 5.6 weeks of paid holiday each leave year. The number of days that works out to depends on how many days a week you work.
Worked example. Working 5 days a week gives 5 x 5.6 = 28 days, which is also the statutory cap. Working 3 days a week gives 3 x 5.6 = 16.8 days. Employers can round entitlement up, never down.
The cap
Statutory entitlement is capped at 28 days. Working 6 or 7 days a week does not push you above 28 days of statutory holiday, though your employer can offer more contractually.
Starters and leavers
If you start or leave part-way through the leave year, you get a proportion of the full entitlement. Enter your start date and the date the leave year ends to pro-rata it.
Irregular hours or zero-hours
If your hours vary week to week, statutory holiday is worked out differently, as pay rather than fixed days. Use the holiday pay calculator for the 12.07% accrual method.
Source: gov.uk holiday entitlement. This is general information, not legal advice.