The Ultimate Guide to Capitalization Rules

Proper capitalization is all about specificity and signaling the start of a new thought.

Nearly every grammar rule in English can be broken at certain times or in certain ways. Styles diverge when the rules are more like suggestions and there’s more than one right way.

The capitalization rules below are nearly unbreakable, but the style choices depend on who you’re writing for.

Capitalization rules

If you follow these guidelines for when to capitalize words, you won’t go wrong.

1. The first word of a sentence

Capitalizing the first word in every sentence shows the reader when you’re moving on to a new idea.

In the example of wrong capitalization above, the reader may think the first period is a typo that should have been a comma.

2. Proper nouns

Common nouns are generic, while proper nouns are specific. For instance, boat is a common noun because it can refer to any boat, but Titanic is a proper noun because it refers to a specific boat. All names are proper nouns and need a capital letter:

• Names of people and animals: Martin Luther King Jr., Cher, Fluffy (a pet)
• Names of places: Australia, the Vatican, Foster Street, the South (referring to the region of the US)
• Names of historical events and time periods: World War II, Tuesday, the Stock Market Crash (but not seasons: fall, winter)
• Names of specific objects, such as vessels: Air Force One, the Statue of Liberty, the Death Star
• Names of organizations, entities, or offices: the United Nations, the Office of the Attorney General, the English Department
• Items named after one of the above: French doors, the Warburg effect, Kafkaesque

You should always capitalize proper nouns.

3. The pronoun I

Always capitalize I when it’s used as a pronoun showing that a person is referring to themselves.

This is a concrete rule that is broken only in rare instances, such as in poetry. Here’s an example from E.E. Cummings, who’s famous for breaking the rules:

i carry your heart with me(i carry it in

my heart)i am never without it(anywhere

i go you go,my dear;and whatever is done

by only me is your doing,my darling)

4. First word of a quote that’s a complete sentence

Integrating quotes into a sentence can be confusing sometimes. The rule is to capitalize the first word of a quote when the quote is a complete sentence, but lowercase it if the quote is not. Quotes that are sentence fragments fit grammatically into the sentence.

5. Acronyms and initialisms

Acronyms and initialisms are two types of abbreviations we form using the first letters of a term. The difference is that we pronounce an acronym as a new word (NATO, NASA, MADD), while we say the individual letters of an initialism (DIY, NAACP, UN). But in both cases, all the letters should be capitalized.

Sometimes after an acronym has been used long enough, it becomes a common noun and no longer needs to be capitalized. Some examples are radar, laser, and scuba.

Capitalization style choices

Besides the rules above, there are lots of cases (pun intended) when capitalization in English is a choice. Let’s look at a few of them.

1. Job and relationship titles

The usual rule in English is to lowercase job and relationship titles unless they’re being used like part of a person’s name, in which case they come immediately before the name:

However, in some types of writing, it’s acceptable to capitalize job titles even when they aren’t used just before a name. You might do this in a resume, in your email signature, or on your company’s website.

2. Titles of works

Whether and how to capitalize titles of works depends on the style guide you’re following. Although style is subjective, you must follow the “rules” of the particular style you’re using. Let’s explore some examples:

• AP style capitalizes only the first word and proper nouns: Chinese spy balloon shot down off coast of South Carolina
• AP style capitalizes all “major words” when mentioning another work: “Everything Everywhere All at Once” was nominated for an Academy Award this year.
• Chicago style lowercases conjunctions and prepositions: Four Theories concerning the Gospel according to Matthew
• APA Style capitalizes all major words and all words with four letters or more: Electromechanical and Robot-Assisted Arm Training for Improving Activities of Daily Living, Arm Function, and Arm Muscle Strength After Stroke

Differences also apply to titles of works in a reference list. For instance, Chicago style capitalizes all titles of works as described above:

García Márquez, Gabriel. Love in the Time of Cholera. Translated by Edith Grossman. London: Cape, 1988.

APA style lowercases titles of works but capitalizes their containers:

Golden, A. R., Griffin, C. B., Metzger, I. W., & Cooper, S. M. (2018). School racial climate and academic outcomes in African American adolescents: The protective role of peers. Journal of Black Psychology, 44(1), 47–73.

3. Headings

Headings are different from titles. Writers use them to divide a text into smaller sections (in this article, the numbered items are headings). Many style guides recommend capitalizing headings in the same way as titles of works, but this is not required.

There are two main capitalization styles for headings: title case and sentence case.

Title case has all major words capitalized and minor words in lowercase.

Example: QuillBot and ChatGPT: The Perfect Partnership for Writing Assistance

Sentence case only capitalizes the first word and any proper nouns

Example: QuillBot and ChatGPT: the perfect partnership for writing assistance

The QuillBot blog now uses sentence case, as evidenced by this article.

4. Company, brand, or product names

Capitalization of business, brand, or product names follows the style chosen by the company that developed them. The following are examples of “camel case.” A capitalized letter in the middle instead of at the beginning creates a sort of hump in the word’s shape, like on a camel’s back:

• iPhone
• eBay
• QuillBot

Sometimes the first letter is capitalized, like in QuillBot, and sometime’s it’s not, like in eBay.

5. The word after a colon or hyphen

Style guides vary when it comes to capitalizing the first word after a colon:

• Chicago style: capitalize if the colon introduces more than one complete sentence
• AP style: capitalize if the colon introduces a complete sentence
• APA style: capitalize if the colon introduces a complete sentence
• MLA style: capitalize if the colon introduces a rule or principle or several related sentences

However, all the style guides recommend capitalizing the first word after a colon if it’s a proper noun or the pronoun I.

The word after a hyphen is typically capitalized in US English if (1) it’s a proper noun or part of a capitalized title and (2) what comes before the hyphen is a standalone word, not just a prefix. However, in UK English and other English variants, don’t capitalize after a hyphen at all:

Breakin’ all the rules

English grammar and spelling rules are rarely rock solid. Instead, they tend to bend or change with time and different audiences.

That’s why it’s vital to have expert guidance. QuillBot’s developers have created the most advanced free writing tools anywhere on the web, and you can count on them to help you manoeuvre through the mess of capitalization rules in English.

Don’t forget to give the Grammar Checker a try when you’re trying to decide between upper and lowercase, mixing up commonly confused words, or switching between English variants.

It’s capital!

Frequently asked questions about capitalization

What words do not get capitalized?

There are no words that are never capitalized in English—it’s not that simple. But unless they appear in a title, common nouns are always lowercased.

What word is always capitalized?

The pronoun I is always capitalized except in rare instances, such as in some poetry.