Result
It depends on what "up" is doing. In most titles it is part of a phrasal verb ("Set Up," "Sign Up," "Grow Up"), where it works as an adverb and is capitalized in every style guide. When it is a preposition with an object ("Up the River," "Climbing up the Hill"), it is two letters long and stays lowercase mid-title in all six major guides.
"Up" (as a Preposition) by Style Guide
| Style guide | "Up" mid-title | Why |
|---|---|---|
| AP | Lowercase | Prepositions of three or fewer letters stay lowercase |
| APA | Lowercase | Short prepositions (three or fewer letters) stay lowercase |
| Chicago | Lowercase | Prepositions are lowercase at any length |
| MLA | Lowercase | Prepositions are lowercase at any length |
| AMA | Lowercase | Prepositions of three or fewer letters stay lowercase |
| Bluebook | Lowercase | Prepositions of four or fewer letters stay lowercase |
"Up" in Phrasal Verbs Is Capitalized
Ask whether a noun follows "up" and completes its meaning. In "Climbing up the Hill," it does, so "up" is a preposition. In "How to Set Up Your Blog," "up" belongs to the verb "set up," so it is capitalized, even though a noun comes after it.
- How to Set Up a WordPress Blog
- Sign Up for Our Newsletter
- What to Do When Your Site Goes Down
- Growing Up Online
The converter on this page recognizes common phrasal verbs, so "Set Up," "Sign Up," and "Back Up" keep their capitals in every style.
When "Up" Is Capitalized as a Preposition
- First word: "Up the Down Staircase."
- Last word: AP, Chicago, and MLA capitalize it ("Time's Up").
- First word of a subtitle: "Mountains: Up Close."
Related Words
"Out", "off", and "on" follow the same two rules: lowercase as prepositions, capitalized in phrasal verbs.
Real Titles With "Up"
- Up in the Air (2009 film): first word
- Set It Up (2018 film): particle and last word
"Up" in Sentence Case
APA reference lists, many news sites, and most UI text use sentence case instead of title case. There, only the first word and proper nouns get capitals, so "up" is lowercase unless it starts the title: "How to set up a wordpress blog." Pick one of the two styles for a whole set of headings rather than mixing them.
Quick Answers
Should "up" be capitalized in a title?
In phrasal verbs ("Set Up"), yes. As a preposition ("Up the River," mid-title), no.
Is "up" capitalized in "Sign Up"?
Yes. "Up" is part of the verb, so it is an adverb and capitalized in every guide.
Is "up" capitalized in APA?
As a preposition, no; APA lists "up" among its short prepositions. In a phrasal verb, yes.