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Deadline calculation guide

How to Calculate a Working-Day Deadline

Most deadline disagreements come from counting rules rather than arithmetic: whether the start date counts, which days are unavailable and whether a stated period means calendar or working days.

4practical sections, a worked example and a free worksheet.

Step 01

Define the counting rule before calculating.

Calendar days move through every date. Working days exclude the weekend pattern and any holiday or closure dates you supply. Weekdays usually mean Monday to Friday, but an organisation or country may use a different working week.

Also decide whether an eligible starting date is day one or whether counting begins on the following eligible date. The UtilHub calculator leaves this as an explicit option because contracts and internal processes differ.

Step 02

Worked example: add 10 working days.

Start on Monday 3 August 2026, add 10 working days, exclude Saturday and Sunday, include no additional holidays and do not count the starting date. The tenth eligible day is Friday 14 August 2026.

If a weekday bank holiday falls inside that period and is entered in the holiday field, the result moves to the next eligible day. If the start date counts, the result instead moves one eligible day earlier.

  • Move one date at a time in the selected direction.
  • Ignore dates that match the chosen weekend pattern.
  • Ignore supplied holiday dates that fall on otherwise eligible days.
  • Stop when the requested number of eligible days has been counted.

Step 03

UK bank holidays need a region.

England and Wales, Scotland and Northern Ireland have different bank-holiday calendars. A calculator should not silently insert one region’s dates for every user. Copy the dates for the relevant nation—or the organisation’s own closure dates—into the optional field.

The maintained regional snapshot below packages the same checked GOV.UK feed as one CSV table and one structured JSON file. It is useful for spreadsheets, prototypes and reproducible planning notes, while the official source remains authoritative if a date changes.

A bank holiday also does not automatically settle a contractual interpretation. The wording in a contract, court rule, service standard or employer policy takes priority.

Step 04

Avoid common deadline errors.

  • Mixing calendar days with working days.
  • Counting the starting day without checking the stated rule.
  • Assuming every UK nation has the same bank holidays.
  • Forgetting office closures that are not public holidays.
  • Using local timestamps when the task only requires date-only arithmetic.

Official regional dates · reusable files

UK bank holidays for 2025–2028.

One maintained snapshot covering England and Wales, Scotland and Northern Ireland, refreshed from the official GOV.UK JSON feed.

England and Wales32 dates1 January 2025 to 26 December 2028
Scotland37 dates1 January 2025 to 26 December 2028
Northern Ireland40 dates1 January 2025 to 26 December 2028
Combined rows109Division, date, weekday, title and substitute-day note

Formats: the CSV is a flat, spreadsheet-ready table; the JSON preserves the source metadata and three regional groups. The files do not add employer closures or decide whether a particular rule treats a date as non-working.

Source: GOV.UK bank holidays. Contains public sector information licensed under the Open Government Licence v3.0. Check the official source before operational or contractual use.

CSV

Flat spreadsheet schema

Columns are division, division_name, date, day_of_week, title and notes. Text cells are protected if a future source value begins like a spreadsheet formula.

JSON

Grouped regional schema

Read dates from divisions[region].events. The top level retains coverage, refresh time, derivative publisher, official source and licence metadata.

GET

Read the public JSON in a browser

The static endpoint needs no key and permits read-only cross-origin GET requests. Cache and revalidate it rather than fetching repeatedly.

const response = await fetch("https://utilhub.co.uk/assets/data/uk-bank-holidays.json");
const data = await response.json();
console.log(data.divisions["scotland"].events);

Free reusable resource

Keep a practical worksheet.

Download a blank, editable file and keep the plan with your own records. No email address is required.

Working-day deadline checklist

Confirm the counting rule, region, holiday dates, closures and final interpretation before sharing a deadline.

Download checklist

Sources and further guidance

References used for this guide.

UK bank holidays

GOV.UK. Official published dates for England and Wales, Scotland and Northern Ireland.

Bank Holidays API

GOV.UK API Catalogue. Documents the official JSON endpoint used to publish regional UK bank-holiday dates.