I have read the Rules of a competition. The text of the Rules include a sentence as follows:

As per stated in the Rules the entrants will be notified by May 30th 2010.

Does the sentence above mean that May 30th is included in the term of notification or not?


If something is supposed to happen by a certain day, it means it is supposed to happen not later than that, so it includes the day as well.

  • Is there any "common practice" on that in US so if someone asks you to, say, "finish something by 30th" than you will (with 99% probability) bring this "something" on 30th (not earlier than that)? ;)
    – ezpresso
    Jan 29 '12 at 22:34
  • @ezpresso: that would depend both on you and on the common practice among people who work on whatever you're finishing. Jan 30 '12 at 0:38
  • 1
    @ezpresso - I would have it finished and ready to present on the 30th. It doesn't need to be turned in on the 29th, but it should be ready to be presented on the 30th, and not at 5 PM, but earlier.
    – Julia
    Jan 30 '12 at 3:08

It means that at some point on May 30th, the entrants should have been notified.

Technically speaking, notifying them at 23:59:59 on May 30th will suffice to meet that criterion, although for business-related requests most people will operate on "standard working hours", so they probably expect you to notify them while they're at the office (e.g. before 5:00 p.m.) rather than hunting down their home address and waking them up after they've gone to bed.


It is decidedly ... ambiguous.

Return it to me by Mar 24th

can be interpreted as the deadline is before the 24th or _on the 24th. The nominal meaning of 'by' in this context is 'before' but pragmatically it means for the purposes of action on the 24th. From this one can infer that as long as, in this instance, the thing is returned sometime on the 24th and can be used on the 24th, then everything is OK. Returning it as 23:59, or really 5pm, is within the rules but might be considered rude.


In a business sense, the phrase "by May 30th" usually means "by close of business on May 30th" (i.e. the end of the business day, typically 5:00 PM in the English speaking world), while the same statement on a legal contract could have the meaning "by 11:59 PM on May 30th" (i.e. the end of the calendar day). So I would say there is an element on contextual interpretation.

This means there is no strict definition as there is some ambiguity, however I believe the term "by" in every case would include the day of the deadline.


I understand "by" in this context to include the named date. So you'd meet the deadline if you replied on that date. However, something like "By the end of business on..." would have removed any ambiguity.

  • 'I understand "by" in this context to include the named date. So you'd meet the deadline if you replied on that date.' might be taken to mean 'I understand "by" in this context to include the named date. So, if you replied on that date, you would certainly meet the deadline.' But others here dispute your interpretation. What if the people setting the deadline do? Mar 2 '21 at 16:56

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