Is Through Capitalized in a Title?

Should the word through be capitalized in a headline or title? In many cases, the answer is “yes,” but there are also cases in which it must not be capitalized. This depends on a number of factors, most importantly the style guide you are using.

In all of these styles, through is always capitalized, even when used as a preposition, since these styles invariably capitalize words with more than three (AMA, AP, APA, New York Times) or more than four letters (Bluebook, Wikipedia).

Chicago and MLA style on the other hand do not capitalize prepositions, no matter how long they are. However, through is not always used as a preposition, and its position in the title also plays a role. Let’s look at the possible cases:

The first and the last word of a title are always capitalized in Chicago and MLA style:

When through is used as an adverb, then it must be capitalized as well:

Through is also capitalized when it is used as an adjective:

But when through is used as a preposition (and is not the first or last word), then it is not capitalized:

It’s usually not hard to tell if through is used as a preposition, because when that is the case, it expresses a relation between two objects, for example, a spatial relation (“The way through the woods”) or a temporal relation (“Fashion through the ages”). Please note that especially in titles, the first object is sometimes implied, as for example in “Lookin’ through the windows” (= somebody is looking through the windows).

By the way, the Chicago Manual of Style used to have the rule to capitalize prepositions when they are stressed, which was illustrated by the example “A River Runs Through It.” However, this rule existed only up to the 15th edition and is no longer valid as of the 16th edition, which was published in 2010.

Thru is a spelling variant of through. In principle, the rules for capitalizing through also apply to thru, but there is one exception: Since thru has only four letters, it must be lowercased not only in Chicago and MLA, but also in Bluebook and Wikipedia style when used as a preposition:

Since Bluebook style does not have the rule to always capitalize the last word of a title, it follows that in this style, thru remains lowercase when it occurs as the last word and is used as a preposition:

When not used as a preposition, thru must be capitalized in any style:

And in AMA, AP, APA, and New York Times Style, thru is capitalized even when used as a preposition:

The rules can be summarized as follows:

Through is capitalized unless all of the following applies:

• you are using Chicago or MLA style
• through is used as a preposition and is not the first or last word of the title

Thru is capitalized unless all of the following applies:

• you are using Chicago, MLA, Bluebook or Wikipedia style
• thru is used as a preposition and is not the first word of the title
• thru is not the last word of the title or you are using Bluebook style

Instead of remembering these rules, you can simply use the Title Case Converter, which automatically capitalizes your titles taking all these rules into consideration!