Counting working days

What counts as a working day

Monday to Friday. Saturdays and Sundays are skipped and every other day counts, including public holidays. The calculator doesn't know about holidays and says so.

Counting a stretch and counting forward are different sums

Counting a stretch and counting forward give answers a whole day apart. The table shows the same week counted each way.

Both are correct answers to different questions. "We will respond within 5 working days" is the second one: the clock starts the day after. "The project ran Monday to Friday" is the first. The business days calculator does whichever you pick, and shows the dates either way so you can see which one you got.

A start date that falls on a weekend has no working day of its own to give up. For example, 0 working days and 1 working day from a Saturday both land on the Monday.

Subtracting, for when the deadline is fixed

If something has to be finished on a date, subtracting tells you the last day you can start. Say the deadline is 25 December and the job takes 10 working days: counting back gives 11 December. By hand it's easy to lose a day here, because two weekends are in the way, not 1.

Business days and payment terms

Net terms are calendar days unless the agreement says otherwise. Net 30 means 30 days, weekends included. Working days turn up in other clauses: notice periods, response times, delivery windows, and terms written as "within 10 business days". If yours says business days, this is the count it means. If it says Net anything, it almost certainly doesn't. How due dates are counted covers the Net and end-of-month rules.

“Within five working days” is ambiguous

It's the most common phrasing in a contract, and it doesn't say when the clock starts. Say you're asked on Monday for something within 5 working days. That's Friday if Monday counts, and the following Monday if it doesn't. Both readings are reasonable, and the two sides of an agreement often hold different ones.

Write the date, not the count. “By Friday 25 September” can't be read 2 ways, and I'd use a date wherever the job allows it. Where the count has to stay, because it is a standing term and not a one-off job, I recommend saying which end is included: “5 working days, not counting the day of the request”.

Public holidays are not skipped

Weekends fall on the same days in most places that use this count. Public holidays depend on the country, often on the region inside it, and on the year, and several move around the calendar. A tool that guessed would give wrong dates somewhere, so the calculator doesn't try.

Count the weekends automatically and take the holidays off by hand. Use whichever calendar governs the agreement. If the question is when money arrives, I'd use the payer's calendar, because a deadline that falls on the other party's public holiday is unlikely to be met.