Date and time notation in the United States

Date and time notation in the United States differs from that used in nearly all other countries. It is inherited from one historical branch of conventions from the United Kingdom.^{[citation needed]} American styles of notation have also influenced customs of date notation in Canada, creating confusion in international commerce.^[1]

In traditional American usage, dates are written in the month–day–year order (e.g. April 24, 2024) with a comma before and after the year if it is not at the end of a sentence^[2] and time in 12-hour notation (6:12 pm).

International date and time formats typically follow the ISO 8601 format (2024-04-24) for all-numeric dates,^[3] write the time using the 24-hour clock (18:12),^[4] and notate the date using a day–month–year format (24 April 2024).^[5] These forms are increasingly common in American professional, academic, technological, military, and other internationally oriented environments.