Capitalization – An overview and guide

Capitalization in English is a matter that confuses not only the non-native speakers. In my experience, preferences vary between organizations and countries around the world. In an attempt to remain consistent in my own writing, I have found the Microsoft Style Guide’s treatise of this topic to be quite helpful and would like to summarize it for the benefit of others in their quest for a universal set of rules.

Since I first published this article in 2008, more and more organizations have changed their style guide to use sentence case for titles and headings. Two examples are UBS and Microsoft, as seen on their websites.

Microsoft style uses sentence-style capitalization. That means everything is lowercase except the first word and proper nouns, which include the names of brands, products, and services.

Sentence-style capitalization

1. Capitalize the first word of a sentence, heading, title, UI label (such as the name of a button or checkbox), or standalone phrase.
2. Capitalize proper nouns.
3. Use lowercase for everything else.

Additional rules

1. Always capitalize the first word of a new sentence. Rewrite sentences that start with a word that’s always lowercase.
2. Don’t use all uppercase for emphasis. (It’s OK to use italic sparingly for emphasis.)
3. Don’t use all lowercase as a design choice. Although all uppercase is used occasionally as a design element, don’t use it in text.
4. Don’t use internal capitalization (such as AutoScale or e-Book) unless it’s part of a brand name.
5. Don’t capitalize the spelled-out form of an acronym unless it’s a proper noun.
6. When words are joined by a slash, capitalize the word after the slash if the word before the slash is capitalized.
   • Examples
     • Country/Region
     • Turn on the On/Off toggle.

Title-case capitalization

1. Always capitalize the first and last words.
   • Example: A Home to Go Back To
2. Don’t capitalize a, an, or the.
   • Example: The President on the Issues
3. Don’t capitalize prepositions of four or fewer letters (such as on, to, in, up, down, of, and for) unless the preposition is the first or last word.
   • Examples
     • To Learn Is to Change Your Life
     • This Is What I Am Looking For
     • Ryse: Son of Rome
4. Don’t capitalize and, but, or, nor, yet, or so.
   • Example
     • Monitoring and Operating a Private or Hybrid Cloud
5. Capitalize all other words, including nouns, verbs (including is and other forms of be), adverbs (including very and too), adjectives, and pronouns (including this, that, and its).
   • Examples
     • Enterprise Agility Is Not an Oxymoron
     • This Is All There Is
     • Teaching Math Over and Over Again, in Less Time Than Before
6. Capitalize the word after a hyphen if it would be capitalized without the hyphen or it’s the last word.
   • Examples
     • Self-Paced Training for Microsoft Visual Studio
     • Microsoft Management Console: Five Essential Snap-Ins
     • Five Essential Snap-ins for Microsoft Management Console
     • Copy-and-Paste Support in Windows Apps
7. Capitalize the first word of labels and terms that appear in UI and APIs unless they’re always lowercase (for example, ls).
8. In programming languages, follow the traditional capitalization of keywords and other special terms.