Does "I need it by September 30th" mean deadline 24:00 the 30th, or deadline 24:00 29th? [duplicate]

Solution 1:

It cannot be turned in on a date later than September 30th. Feel free to hand it in today, but it will be considered late on October 1st.

Here is an example: In the United States, the due date for tax returns is April 15th, but there is no time of day expressed: http://www.irs.com/articles/2015-deadlines-filing-2014-tax-returns

As such, it is inferred that you must file before the first second of April 16th. http://www.taxact.com/filing-notice.asp

Solution 2:

Here in the UK at least, such an instruction would normally mean "by close of business on September 30th". It's somewhat ambiguous though, and there are certainly clearer ways the request could be worded.