Writing & StyleStyle guide
Mr. vs. Mr Formatting
Mr. versus Mr is primarily a regional and house-style formatting choice. Chicago uses the period-ending form, while Cambridge’s British entry presents Mr without a period, so consistency with the chosen style matters.
Both “Mr.” and “Mr” are established style forms. Chicago uses “Mr.”; Cambridge’s British entry uses “Mr” without a period.
Key details
Core IssueThe honorific may be styled “Mr.” or “Mr” depending on regional and house style; Cambridge’s British entry uses Mr, while Chicago examples use Mr.
Phrase Roleformatting the honorific before a man’s name
Registergeneral to professional
Important caveats
Regional Form
Cambridge’s British-facing dictionary entry presents “Mr” without a period.
Style Boundary
Follow the document’s regional or house style consistently rather than treating one established form as universal grammar.
Further guidance
Chicago Form
Chicago style examples use “Mr.” with a period.
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.
- MR — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Documents British-style Mr as a title before a man’s name
- Chicago Q&A — abbreviations such as Mr. and Dr. (opens in a new tab)The Chicago Manual of Style / University of Chicago Press · Chicago examples use period-ending Mr. and Dr. and treat them as familiar title abbreviations