What Is Sentence Case?
Sentence case capitalizes only the first word of a title, the first word after a colon and any proper nouns — The Effects of Sleep on Exam Performance becomes Effects of sleep on exam performance. APA 7 requires it for article and book titles in reference lists. This page unpacks the definition, the mistakes graders see most, and a worked example you can pattern-match against your own draft.
James Parker, MLS
Citation & Formatting Reviewer · Master of Library Science; 9 years as a reference librarian coaching APA, MLA and Chicago styles
Quick answer
Sentence case capitalizes only the first word of a title, the first word after a colon and any proper nouns — The Effects of Sleep on Exam Performance becomes Effects of sleep on exam performance. APA 7 requires it for article and book titles in reference lists.
On this page · 4 sections
The definition, precisely
Sentence case treats a title like a sentence: capitalize the first word, capitalize the first word after a colon (it functions as a new sentence), and capitalize proper nouns wherever they fall. Everything else — nouns that are not proper, verbs, mid-title adjectives — stays lowercase. So The Effects of Sleep Restriction on Working Memory becomes Effects of sleep restriction on working memory, but a study of MRI accuracy keeps MRI capitalized and a history of English departments keeps English. The format gets its name from that resemblance to an ordinary sentence.
Students meet sentence case in one dominant context: APA 7 reference lists. Article titles, book titles, chapter titles and webpage titles all sit in sentence case there, while the journal name beside them keeps title case and its italics. The asymmetry looks like a mistake the first time; it is the rule, and it exists because sentence case removes hundreds of judgment calls — no deciding whether OF counts as a short preposition, no hyphenated-word debates. One rule, applied the same way to every entry.
Converting a title case title is mechanical if you know what survives. Proper nouns and their adjectives survive: Freud, Victorian, Chicago. Acronyms and initialisms survive: FDA, IQ, GPA. The first word and the first word after a colon survive. Everything else drops to lowercase. The error to hunt in the final pass is the opposite direction too — an entry that forgot to convert, sitting in title case between twenty sentence-case neighbors, is the single most visible inconsistency a reference page can carry.
The four mistakes graders see most
Every one of these shows up in a stack of sixty papers — usually more than once. Each pairs the error with the fix, so the table doubles as a pre-submission check.
| Common mistake | The fix |
|---|---|
| Lowercasing proper nouns and acronyms when converting a title. | Sentence case never touches names: English, Freud, MRI, FDA keep their capitals wherever they sit in the title. |
| Leaving the subtitle lowercase after the colon. | The word after a colon always capitalizes in sentence case: Night shifts: How hospitals learned to count fatigue. |
| Applying sentence case to the journal name in an APA reference. | Journal names keep title case and their italics. Only the article title beside them drops to sentence case. |
| Mixing sentence and title case across entries in one list. | APA references are sentence case throughout for titles. One unconverted entry reads as an unfinished edit pass. |
A worked example
The same article appears differently in two lists. In an APA 7 reference: Rivera, D. (2024). Effects of sleep restriction on working memory in college athletes. Journal of Sports Science, 41(3), 88-102 — article title sentence case, journal name title case and italicized. In an MLA 9 works-cited page the article title flips to title case, because MLA never uses sentence case for cited titles. Same source, two systems, and the grader checks which list the entry sits in before judging the capitals.
Pattern-match your own draft against this example rather than against the definition: concrete cases transfer better than abstract rules, and the example shows what the rule looks like when it is done right.
How sentence case differs from its neighbors
Sentence case is not title case, which capitalizes all major words and governs MLA works-cited titles and APA journal names. It is not lowercase-everything, which is what students who half-remember the rule produce — proper nouns still capitalize, always. And it is not a casual style you may choose freely: within APA 7 references it is mandatory, and its appearance in an MLA works-cited entry is a cross-style contamination error that reads like copied formatting from an APA template. Check which list an entry sits in before touching its capitals.
Boundary confusion is where most grading deductions live: the term is understood roughly but applied against the wrong neighbor. Pin the boundary above and the term stops being fuzzy in practice, which is what the rubric is actually testing.
What's your next step?
Two taps to the exact page that unblocks this paper.
The 30-second check
Skim the four mistakes above against your draft. Any hit is a fix you can make in minutes — and the format row of the rubric is where they all live.
Questions with exact numbers
Forty-plus student questions — word counts, source math, citation edge cases — answered with the real arithmetic.
Browse the Q&ARelated term: Hanging Indent — the neighbor this term is most often confused with. Reading the pair together is how the boundary sticks.
Frequently asked questions
4 answered1When do I use sentence case?
Chiefly inside APA 7 reference lists, where article, book, chapter and webpage titles all sit in sentence case. It also appears in Chicago's lowercased headline variants and in much scientific publishing. MLA does not use it for cited titles at any point.
2What stays capitalized in sentence case?
Three things: the first word of the title, the first word after a colon, and proper nouns — including acronyms like MRI and adjectives like Victorian. Everything else drops to lowercase, even long words and even nouns. Nouns like government or university stay lowercase unless they are part of a proper name.
3Does the first word after a colon capitalize?
Yes, in sentence case and in every major title style. The colon resets the capitalization: the rule functions the same way a new sentence does, which is the whole logic of the format's name. APA, MLA and Chicago all agree on this one point.
4Why does APA use sentence case in references?
Consistency and error reduction. Title case forces a judgment call on every short word — is via a preposition, is so a conjunction — and different writers decide differently. Sentence case removes the decisions, so reference lists from different authors come out identical in pattern.
James Parker, MLS
Citation & Formatting Reviewer · Master of Library Science; 9 years as a reference librarian coaching APA, MLA and Chicago styles