They vary from formal to informal, and there are differences between British and American English.
The following table shows some typical formats:
FORMAT | BRITISH: DAY-MONTH-YEAR | AMERICAN: MONTH-DAY-YEAR |
---|---|---|
A | The Fifth of January, 2016 | January the Fifth, 2016 |
B | 5th January 2016 | January 5th, 2016 |
C | 05 January 2016 | January 05, 2016 |
D | 05/01/2016 | 01/05/2016 |
The format to use is a question of formality, politeness and personal choice.
Generally, the longer formats, such as B or C, are more polite (since they show more respect for the reader).
Shorter formats, such as D, are used in less formal situations, for example a memo, a letter between friends or an impersonal business letter.
Format A is extremely formal and mainly used on printed items, for example a wedding invitation.
The numerical formats may use a full stop (.) or a hyphen (-) instead of a slash (/), for example: 05.1.2016 or 01-05-16.