Rules for Capitalization  

The capitalization of a word (meaning its first letter is in the upper case) often depends upon its context and placement within a sentence. While there are some words that are always capitalized no matter where they appear in a sentence—such as “proper” nouns and adjectives, as well as the first-person pronoun I—most words are only capitalized if they appear at the beginning of a sentence.

Determining when to capitalize words in the titles of creative or published works (such as novels, films, essays, plays, paintings, news headlines, etc.) can be very difficult because there is no single, generally accepted rule to follow. However, there are some standard conventions, which we’ll discuss a little further on.

The first word of a sentence is always capitalized. This helps the reader clearly recognize that the sentence has begun, and we make it clear that the sentence has ended by using terminal punctuation marks (e.g., periods, exclamation points, or question marks).

We also capitalize the first letter of a sentence that is directly quoted within another sentence. This is known as direct speech. For example:

Sometimes, a portion of a larger statement will be quoted as a complete sentence on its own; this is especially common in journalistic writing. To preserve capitalization conventions, we still usually capitalize the first letter of the quoted speech (if it functions as a complete independent sentence), but we surround the capital letter in brackets to make it clear that the change was made by the person using the quotation. For instance:

Note that we do not capitalize the first word in the quotation if it is a word, phrase, or sentence fragment incorporated into the natural flow of the overall sentence; we also do not set it apart with commas:

Sometimes, a trademark or brand name will begin with a lowercase letter immediately followed by an uppercase letter, as in iPhone, eBay, eHarmony, etc. If writers decide to begin a sentence with such a trademarked word, they may be confused about whether to capitalize the first letter since it is at the beginning of a sentence, or to leave the first letter in lowercase since it is specific to the brand name. Different style guides have different requirements, but most guides recommend rewording the sentence to avoid the issue altogether:

Proper nouns are used to identify a unique person, place, or thing (as opposed to common nouns, which identify generic or nonspecific people or things). A proper noun names someone or something that is one of a kind; this is signified by capitalizing the first letter of the word, no matter where it appears in a sentence.

The most common proper nouns are names of people, places, or events:

Proper nouns are similarly used for items that have a commercial brand name. In this case, the object that’s being referred to is not unique in itself, but the brand it belongs to is. For example:

The names of organizations, companies, agencies, etc., are all proper nouns as well, so the words that make up the name are all capitalized. However, unlike the nouns of people or places, these often contain function words (those that have only grammatical importance, such as articles, conjunctions, and prepositions), which are not capitalized. For example:

These are often made into acronyms and initialisms, which we’ll discuss a bit later.

Appellations are additional words added to a person’s name. These may be used to indicate respect for a person (known as honorifics) or to indicate a person’s profession, royalty, rank, etc. (known as titles). Some appellations are always abbreviated before a person’s name, such as Dr. (short for Doctor), Mr. (short for Mister), and Mrs. (originally a shortened form of Mistress), and some may be used in place of a person’s name altogether (such as Your Honor, Your Highness, or Your Majesty).

Appellations are considered a “part” of the person’s name and are also capitalized in writing as a proper noun. For example:

Normal words can also function as appellations after a person’s name to describe his or her appearance, personality, or other personal characteristics; these are formally known as epithets. They are usually accompanied by function words (especially the article the), which are not capitalized. For example:

Proper adjectives are formed from proper nouns, and they are also capitalized. They are often made from the names of cities, countries, or regions to describe where something comes from or to identify a trait associated with that place, but they can also be formed from the names of people. For example:

Sometimes, a word that began as a proper adjective can lose its “proper” significance over time, especially when formed from the name of a fictional character. In these cases, the word is no longer capitalized. Take the following sentence:

The word quixotic was originally a proper adjective derived from the name “Don Quixote,” a fictional character who was prone to foolish, grandiose behavior. Through time, it has come to mean “foolish” in its own right, losing its association to the character. As such, it is no longer capitalized in modern English.

Another example is the word gargantuan. Once associated with the name of a giant in the 16th-century book Gargantua, it has come to mean “huge” in daily use. Since losing its link with the fictional monster, it is no longer capitalized:

While proper nouns, proper adjectives, and the first word in a sentence are always capitalized, there are other conventions for capitalization that have less concrete rules.

Traditionally, words for or relating to the Judeo-Christian God or to Jesus Christ are capitalized, a practice known as reverential capitalization. This is especially common in pronouns, though it can occur with other nouns associated with or used as a metaphor for God. For example:

However, this practice is one of style rather than grammatical correctness. It is becoming slightly less common in modern writing, especially in relation to pronouns, and many modern publications (even some editions of the Bible) tend not to capitalize pronouns associated with God or Jesus Christ (though nouns such as “the Lamb” or “the Almighty” still tend to be in uppercase).

Finally, note that when the word god is being used to describe or discuss a deity in general (i.e., not the specific God of Christian or Jewish faith), it does not need to be capitalized. Conversely, any name of a specific religious figure must be capitalized the same way as any other proper noun, as in Zeus, Buddha, Allah, Krishna, etc.

Acronyms and initialisms are abbreviations of multiple words using just their initial letters; like the initials of a person’s name, these letters are usually capitalized. Acronyms are distinguished by the fact that they are read aloud as a single word, while initialisms are spoken aloud as individual letters rather than a single word. (However, because the two are so similar in appearance and function, it is very common to simply refer to both as acronyms.)

Because acronyms are said as distinct words, they are usually (but not always) written without periods. In some cases, the acronym has become so common that the letters aren’t even capitalized anymore.

For example:

It’s worth noting that in British English, it is becoming increasingly common to write acronyms of well-known organizations with only the first letter capitalized, as in Nafta (North American Free Trade Agreement) or Unicef (United Nations International Children's Emergency Fund), while initialisms, such as UN or UK, are still written in all capital letters.

Like acronyms, it is most common to write initialisms without periods. However, in American English, it is also common to include periods between the letters of some initialisms. This varies between style guides, and it is generally a matter of personal preference; whether you use periods in initialisms or not, be sure to be consistent.

Here are some examples of common initialisms (some with periods, some without):

Notice that the h in Ph.D. remains lowercase. This is because it is part of the same word as P (Philosophiae); it is spoken aloud as an individual letter to help make the initialism distinct. While this mix of uppercase and lowercase letters in an initialism is uncommon, there are other instances in which this occurs. Sometimes, as with Ph.D., the lowercase letters come from the same word as an uppercase letter; other times, the lowercase letter represents a function word (a conjunction, preposition, or article). For example:

Finally, there are two initialisms that are always in lowercase: i.e. (short for the Latin id est, meaning “that is”) and e.g. (short for the Latin exempli gratia, meaning “for example”). The only instance in which these initialisms might be capitalized is if they are used at the beginning of a sentence, but doing so, while not grammatically incorrect, is generally considered aesthetically unappealing and should be avoided.

In conversational writing, especially with the advent of text messages and online messaging, many phrases have become shortened into informal abbreviations (usually initialisms, but occasionally said aloud as new words). They are usually written without periods and, due to their colloquial nature, they are often left in lowercase. While there are thousands of conversational abbreviations in use today, here are just a few of the most common:

Because these are all very informal, they should only be used in conversational writing.

There is much less standardization regarding how to capitalize titles or article headlines; different style guides prescribe different rules and recommendations.

That said, it is generally agreed that you should capitalize the first and last word of the title, along with any words of semantic significance—that is, nouns, pronouns, verbs, adjectives, and adverbs—along with proper nouns, proper adjectives, acronyms, and initialisms. “Function words,” those that primarily add grammatical meaning rather than anything substantial (prepositions, articles, and conjunctions), are generally left in lowercase. This convention is sometimes known as title case, and some style guides recommend following it without exception, even for longer function words like between or upon.

For example:

Some words can pose problems because they can in some instances be prepositions and in other instances be adverbs. For example, in the phrasal verb take off, off is functioning adverbially to complete the meaning of the verb, so it would be capitalized in a title:

Another group of words that often gives writers problems is the various forms of the verb to be, which conjugates as is, am, are, was, were, been, and being. Because many of its forms are only two or three letters, writers are often inclined not to capitalize them; however, because to be is a verb, we should always capitalize it when using title case:

Function words are usually not capitalized in title case, but longer function words (such as the conjunctions because or should or the prepositions between or above) are often considered to add more meaning than short ones like or or and. Because of this, it is a common convention is to capitalize function words that have more than three letters in addition to “major” words like nouns and verbs. Here’s how titles following this convention look:

Some style guides specify that only function words that are longer than four letters should be capitalized. Following this convention, the first three examples would remain the same, but the word over in the fourth example would remain lowercase. However, the “longer than three letters” rule is much more common.

When a compound word features a hyphen, there are multiple ways to capitalize it in a title. Because compound words always serve as nouns or adjectives (or, rarely, verbs), we always capitalize the first part of the compound. What is less straightforward is whether to capitalize the word that comes after the hyphen. Some style guides recommend capitalizing both parts (so long as the second part is a “major” word), while others recommend only capitalizing the first part. For example:

Certain style guides are very specific about how to capitalize hyphenated compounds, so if your school or employer uses a particular guide for its in-house style, be sure to follow its requirements. Otherwise, it is simply a matter of personal preference whether hyphenated compounds should be capitalized in full or in part; as always, just be consistent.

Some multiple-word compounds are formed with function words (typically the article the, the conjunction and, or the preposition in) between two other major words. While capitalizing the major words in the compound is optional and up to the writer’s personal preference, the function words will always be in lowercase:

The only exception to this rule is when writers choose to capitalize every word in the title.

To eliminate the possible confusion caused by short “substance” words (e.g., forms of to be), long function words (e.g., because or beneath), and hyphenated compounds, some publications choose to simply capitalize every word in a title, regardless of the “types” of words it may contain. This is sometimes known as “start case” or “initial case.” For instance:

This is especially common in journalism and online publications, but it is usually not recommended for academic or professional writing.

“Sentence case” refers to titles in which only the first word has a capital letter, the same way a sentence is capitalized. (Again, proper nouns, proper adjectives, acronyms, and initialisms remain capitalized.) As with start case, sentence case is useful because it eliminates any possible confusion over which words should be capitalized. Titles following this convention look like this:

Sentence case is not typically recommended by academic or professional style guides, though this is not always true. Some magazine and news publications use the style for their headlines as well, as do many websites.

When a piece of work has both a main title and a secondary subtitle (separated by a colon), we apply the same capitalization rules to both—that is, the same types of words will be in uppercase or lowercase depending on which style is being used. We also capitalize the first word after the colon, treating the subtitle as its own. For example:

This convention is also true in academic essays, whose subtitles tend to be longer and more detailed, giving the reader a brief explanation of what the essay is about:

Note that if the main title is written in sentence case, then we only capitalize the first word of the subtitle (after the colon):

However, this style is generally only used when a title appears in a list of references in an essay’s bibliography (individual style guides will have specific requirements for these works cited pages).

Sometimes a subtitle acts as an alternate title; in this case, the two are often separated with a semicolon or a comma, followed by a lowercase or (though the specific style is left to the writer’s or publisher’s discretion). However, the alternate title is still capitalized the same way as the main title, with the first word after or being capitalized even if it is a short function word. For example:

Headings are titles that identify or introduce a specific section within a larger academic essay or business document. In general, headings will be capitalized in the same manner as the document’s title, usually having the first and last word capitalized as well as any nouns, adjectives, adverbs, and verbs (and, depending on the style guide being followed, any prepositions or conjunctions longer than three letters).

Sometimes a written work will have multiple subheadings of sections that belong within a larger heading. It is common for subheadings to be written in sentence case, but most style guide have specific requirements for when this can be done (for instance, if the subheading is the third or more in a series of headings), if at all.

Ultimately, unless your school or employer follows one specific style guide, it is a matter of preference to decide how the title is formatted. No matter which style you adopt, the most important thing is to be consistent throughout your body of writing.