DateAndTimeCalculator.org

Deadline Calculator

Work out a deadline date from a start date and a period in working days or calendar days, and see how much time is left.

Last reviewed: 30 July 2026

Only applies when counting calendar days.

National holidays only. Regional, state and company holidays are not included. Calendar last reviewed 30 July 2026.

Weekend days

Ticked days are treated as non-working. Change these if your week does not run Monday to Friday.

How this calculation works

The deadline is found by counting the allowed period forward from the day the clock starts. Counting begins the following day, so a five working day deadline set on a Monday falls on the following Monday, giving five full days of work.

Working days against calendar days

Working days skip the weekend and any public holidays for the country you choose. Calendar days count everything. The difference is substantial: ten working days set on 20 December in England runs to well into January, while ten calendar days ends on the 30th.

Deadlines landing on a closed day

A calendar-day deadline can land on a Sunday or a bank holiday. Many agreements say such a deadline moves to the next working day, but not all do, so the behaviour is yours to choose. When the option is switched on, the result shows both the raw date and the date it moved to.

The countdown

Days remaining are measured from today in your own time zone, counting today as one of the days you still have. When the deadline has passed, the result says how far past it is rather than showing a negative number.

Worked example

A 10 working day deadline set on Monday 21 December 2026, England and Wales

  • Christmas Day, the Boxing Day substitute and New Year's Day are all skipped.
  • Two full weekends fall inside the period.
  • The deadline lands on Monday 11 January 2027.
  • That is 21 calendar days after the clock started, not 14.

The same period counted in calendar days would have expired on 31 December 2026 — nearly two weeks earlier.

Data and limitations

  • National holidays only. Holiday calendar last reviewed 30 July 2026.
  • Deadlines are calculated as whole dates, with no cut-off time of day.
  • This is a planning tool, not legal advice. Where a deadline is statutory or contractual, confirm the counting rule and the applicable holiday calendar against the agreement itself.

Frequently asked questions

Should I use working days or calendar days?

Read the wording that set the deadline. "Within 14 days" almost always means calendar days, including weekends and holidays. "Within 10 working days" or "10 business days" excludes them. Service level agreements and statutory response times usually specify which, and getting it wrong is the most common cause of a missed deadline.

Does the deadline day itself count?

The deadline is the last day you have, so work delivered on that day is on time. The countdown shows how many days remain including today, so "3 working days remaining" means today plus two more.

What happens if the deadline lands on a weekend or a holiday?

With calendar days it can, and the calculator says so. Many agreements move such a deadline to the next working day, so an option is provided to do that. Check your agreement, because the rule is not universal.

Is the countdown based on my computer clock?

Yes. The days remaining are measured from today in your own time zone. If your device clock or zone is wrong, the countdown will be too, though the deadline date itself is unaffected.

Can I use this for a notice period?

It will calculate the dates, but notice periods often have their own rules about when the period starts and whether it runs in calendar weeks or months. Use the result as a guide and confirm it against the contract wording.