UK Holiday Entitlement Calculator 2026
A free UK holiday entitlement calculator I built with plain JavaScript. It covers full-time, part-time, shifts, the 12.07% irregular-hours rule, starters, leavers and holiday pay owed, using GOV.UK rules.
A project I built. The summary below is what it does. I can build this kind of page for a business.
- HTML
- CSS
- JavaScript
- Node test runner
- Vercel
- Frontend
The UK Holiday Entitlement Calculator works out statutory annual leave under the Working Time Regulations: 5.6 weeks a year, capped at 28 days. It handles four working patterns: days per week, hours per week with days of different lengths, regular shift patterns, and irregular hours.
For irregular-hours and part-year workers it uses the 12.07% accrual that applies to leave years starting on or after 1 April 2024. It shows the exact hours earned in a pay period, the GOV.UK rounding and rolled-up holiday pay. For everyone else it covers a full leave year, starting part-way (one-twelfth per month started, rounded up to the next half day), leaving part-way (pro-rated by calendar days) and short contracts. Leavers can enter leave already taken and their pay to see the holiday pay they are owed.
Every result comes with numbered working, a month-by-month chart of the leave year and the 2026 bank holidays for England and Wales, Scotland and Northern Ireland. Results can be shared by URL, copied or printed.
It is plain HTML, CSS and JavaScript with no build step, no tracking and no API key. The logic is unit-tested against all 19 worked examples in GOV.UK's holiday entitlement guidance, plus the 12.07% example, and the page has FAQ, WebApplication and breadcrumb structured data.
// context
How this page fits the rest of the site.
UK Holiday Entitlement Calculator 2026 is work I built and can extend. The summary above is the scope of this repository. A business version can add accounts, a server, or a design that matches the brand.
Technologies are the ones listed on the card. A live demo button appears only when a page is actually published. GitHub is the source. If the repository and this write-up disagree, trust the repository and send a correction from the contact page.