How to Count Deadlines and Notice Periods

Why deadline counting is a rule, not a guess

A deadline is a legal or contractual instruction, and the way days are counted is part of it. Two people can count 14 days from the same event and reach different dates, each in good faith. The difference is usually whether the day of the event counts, and what happens if the last day is a weekend or a holiday.

This article describes the common patterns and shows how to work them out with a calculator. It is general information, not legal advice. The rule that applies to you is the one in your contract, your statute or your authority’s instructions.

The day of the event is usually not counted

Many legal systems start counting on the day after the triggering event. The European Union’s regulation on time limits, 1182/71, provides that when a period is expressed in days, the day on which the event occurs is not counted. The German civil code takes the same approach for periods that are triggered by an event: the day of the event does not count.

With this rule, a period of 14 days that is triggered on Thursday 22 October 2026 begins on Friday 23 October and ends at the end of Thursday 5 November 2026. In calendar terms, it is simply the event date plus 14 days.

The rule is different when a period starts at the beginning of a day. In that case, the first day usually counts, as in a contract that starts on 1 February. German law applies the same logic to age: the day of birth counts, which is why a person reaches a new age at the end of the day before the birthday.

When the period ends

A period in days ends at the end of its last day. For periods in weeks, months or years, the common rule is that it ends on the day that has the same weekday or the same date as the event. A one-week period triggered on Thursday 22 October 2026 ends at the end of Thursday 29 October 2026.

A one-month period triggered on 22 October ends on 22 November, and a one-month period triggered on 31 January ends on the last day of February, because there is no 31 February. The EU regulation states this explicitly: if the final month has no corresponding day, the period ends on the last day of that month.

Check the exact wording. A period that runs from a date can end one day earlier than a period that runs after an event, because the first day counts in one case and not in the other.

Weekends and public holidays

Weekends and holidays inside a period normally count, unless the rule says working days. The common exception concerns the last day: if the period ends on a Saturday, Sunday or public holiday, many rules move the end to the next working day.

The EU regulation provides this, and the German civil code does the same for declarations and payments, with some exceptions, for instance for certain notice periods. Because of such exceptions, you should not assume that the extension applies to your case.

With a 30-day period triggered on Thursday 22 October 2026, the last day is Saturday 21 November 2026. Under a rule that extends the end to the next working day, it would be Monday 23 November 2026. Under a rule without extension, it would stay on the Saturday.

Sent or received

Many deadlines depend on a receipt and not on sending. A notice that must reach the other party within 14 days can be late if it is posted on the last day. Others count from the date of posting, or from the date a message is delivered to the recipient’s mailbox.

Time zones and times of day can matter, especially for electronic messages and across borders. A deadline that ends at the end of a day in one country has ended before the day does somewhere else.

The safe approach is to act well before the last day, and to keep proof of the date: a receipt, a delivery confirmation or a time-stamped email.

A practical routine

1. Find the exact rule: contract clause, statute or instruction.
2. Identify the triggering event and its date.
3. Decide whether the first day counts.
4. Calculate the last day with a calculator and note the weekday.
5. Check whether the end moves for weekends and holidays.
6. Set a reminder a few days earlier, and keep proof of what you did.

If a lot depends on the outcome, ask a lawyer or the authority concerned. A calculator tells you what the arithmetic gives, and a professional tells you what the rule means.

Using the calculator

On the Add or subtract tab, enter the date of the triggering event, choose Add and type the number of days, weeks or months. The result shows the end date and its weekday, so you can see at once whether it falls on a weekend.

To count a period that includes the first day, subtract one day from the result or tick the include option on the days-between tab. Always write down which of the two you used.