Comma in Dates
Comma use in dates is tied to the date order and house style. Microsoft’s month–day–year convention includes a comma before the year, while Australian Government day–month–year style omits a comma. Apply the punctuation that belongs to the chosen date format.
In month–day–year prose, a comma commonly separates the day from the year (“July 31, 2016”). In day–month–year styles such as Australian Government style, no comma is used (“31 July 2016”).
Key details
Important caveats
Order Boundary
Do not transfer the comma rule from one date order to another automatically.
Style Boundary
Microsoft and Australian Government guidance illustrate different punctuation conventions tied to their preferred date orders.
Further guidance
Practical Application
Apply punctuation according to the date order your style uses. In month–day–year prose, separate the day from the year with a comma; in day–month–year styles such as Australian Government style, do not insert that comma. Keep one date system consistent within a document unless quoted material requires otherwise.
Reader Check
Is the date written month–day–year or day–month–year, and does the punctuation match the governing regional or house style?
Worked Example
Write “July 31, 2016” in a month–day–year style, but “31 July 2016” in a day–month–year style; do not mechanically copy the comma from one order into the other.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Date and time terms — Microsoft Style Guide (opens in a new tab)Microsoft · Official Microsoft house-style guidance for dates and times, including date ordering and formatting examples.
- Dates and time — Australian Government Style Manual (opens in a new tab)Australian Government Style Manual · Australian Government guidance for day–month–year dates, ordinal dates, decades, centuries, time zones, and en-dash spacing in date/time spans