Title Case vs Sentence Case: Rules, Examples, and When to Use Each
Title case capitalises major words; sentence case capitalises only the first word and proper nouns. Picking the right one signals which house style you're writing in.
If you've ever stared at a draft heading and wondered whether to write "How to Write a Great Blog Post" or "How to write a great blog post", you've stumbled into one of the small but persistent fault lines in English-language publishing. The two styles — title case and sentence case — look almost identical, follow different rules, and signal different things about who you write for.
This piece covers what each style actually means, where the four major style guides disagree, and how to choose between them without re-reading a 1,200-page style manual every time you write a heading.
The one-sentence definitions
Title case capitalises the first letter of every major word in a heading or title. Minor words — short articles, conjunctions, and prepositions — are usually lowercased. Example: The Old Man and the Sea.
Sentence case capitalises only the first word of a heading and any words that would be capitalised in normal prose (proper nouns, brand names, the pronoun I). Example: The old man and the sea.
That's the entirety of the high-level distinction. The complications start the moment you ask which words count as "major" and which count as "short enough to lowercase".
Why this matters
Beyond the obvious aesthetic difference, the choice carries signals that experienced readers — and editors — read instantly:
- Title case feels formal, traditional, and editorial. It's the default in print book titles, academic papers, US journalism, news headlines, and most legal documents.
- Sentence case feels modern, software-y, and conversational. It dominates UI design, technical documentation, and a growing share of digital-native publications (the BBC, the Guardian's online sub-headings, Apple's marketing copy, most SaaS dashboards).
In other words, your case choice tells the reader whether they're reading something that wishes it were a book or something that wishes it were an app. Pick deliberately.
The four big style guides — and what they disagree about
AP Style (Associated Press)
Used by most US newsrooms.
- Capitalise the first and last word.
- Capitalise all "principal" words (nouns, verbs, adjectives, adverbs, pronouns).
- Lowercase articles (a, an, the), coordinating conjunctions (and, but, or, for, nor), and prepositions of three letters or fewer (in, of, on, at, to, by).
- Capitalise prepositions of four or more letters (with, from, into, over, about).
Example: AP Style Has Strong Opinions About Headlines
Chicago Manual of Style
Used in book publishing and most US academic writing.
- Capitalise the first and last word.
- Capitalise major words (nouns, verbs, adjectives, adverbs, pronouns) — same as AP.
- Lowercase articles, coordinating conjunctions, and prepositions, regardless of length.
- Capitalise the second part of a hyphenated compound (A Self-Made Man).
The key Chicago/AP split: AP capitalises prepositions of 4+ letters, Chicago lowercases all prepositions.
Example (Chicago): Chicago Is Stricter about Prepositions than AP — note "about" is lowercased.
MLA (Modern Language Association)
Used in literature and humanities papers.
- Capitalise first and last word.
- Capitalise nouns, pronouns, verbs, adjectives, adverbs, and subordinating conjunctions (although, because, if, when).
- Lowercase articles, coordinating conjunctions, prepositions (any length), and the to in infinitives.
MLA is the strictest about lowercasing — even longer prepositions stay lowercase.
APA (American Psychological Association)
Used in psychology, social sciences, and education writing.
APA has two rules depending on context:
- In references and headings: sentence case. Only the first word, proper nouns, and the first word after a colon are capitalised.
- In headings within the body: title case, with rules similar to Chicago.
This is part of why APA papers feel inconsistent to outsiders — the rule changes depending on what you're capitalising.
The four-letter preposition trap
The single biggest source of inconsistency in title-cased writing is the preposition rule.
- AP: "How to Write with Confidence" → with is capitalised (it's a 4-letter preposition).
- Chicago: "How to Write with Confidence" → with is lowercased (Chicago lowercases all prepositions).
- MLA: "How to Write with Confidence" → with is lowercased.
If you can't remember which guide you're following, the safest fallback is to capitalise nothing that is unambiguously a preposition. You'll be wrong on AP but right on everything else.
Sentence case rules (it's simpler — sort of)
Sentence case has fewer rules but more judgement calls about proper nouns:
- Capitalise the first word of the heading.
- Capitalise the first word after a colon if what follows is an independent clause (Chicago) or always (APA references).
- Capitalise proper nouns as you would in any sentence: names of people, places, organisations, brand names, days of the week, months, languages, nationalities.
- Capitalise acronyms and initialisms that are normally capitalised (HTML, NATO, BBC).
- Don't capitalise common nouns even if they feel important in context. The temptation is real: "Our New Feature is Live" looks more emphatic than "Our new feature is live", but it's the latter that's correct sentence case.
Example: How to set up two-factor authentication on GitHub
Here, GitHub is capitalised because it's a brand name. Two-factor authentication is lowercased because it's a generic technical term, not a proper noun.
When to use which: a working rule
If you have no house style and you're picking from scratch, here is a defensible default:
| Content type | Recommended case |
|---|---|
| Long-form articles, essays, white papers | Title case (Chicago) |
| News articles | Title case (AP if US, sentence case if UK) |
| Blog posts (most modern) | Sentence case |
| Email subject lines | Sentence case |
| Section headings inside body text | Sentence case |
| Book titles | Title case (Chicago) |
| Product names | Title case (always) |
| Button and UI labels | Title case (short) or sentence case (longer phrases) |
| Tooltip text and error messages | Sentence case |
| Academic paper titles | Whatever the journal requires |
When in doubt: sentence case for screens, title case for paper. Imperfect rule, but right more often than not.
The shortcuts you can actually rely on
Three things worth memorising even if you don't memorise anything else:
- First and last words are always capitalised, in every style guide, in title case.
- Articles, coordinating conjunctions, and short prepositions are lowercase in title case — across all four major guides.
- Proper nouns are always capitalised, in sentence case or title case, regardless of position.
If you remember those three, you'll be right on 80% of headings, and the disagreements only affect the edge cases.
Converting between them
Manually re-casing a heading is error-prone — it's easy to miss a stray capital. The case converter handles both title case (AP-style by default) and sentence case in one click, along with ten other cases (UPPERCASE, lowercase, camelCase, snake_case, and the rest). Paste your heading, click the case you want, copy the result.
The Title Case option uses AP-style rules — articles, conjunctions, and short prepositions lowercased; everything else capitalised. If you're publishing under a Chicago house style, you'll want to manually lowercase any prepositions of four or more letters that the converter capitalised.
A note on UI text
Software companies have largely converged on sentence case for UI labels, for two reasons. First, sentence case is easier to localise — many languages don't have a concept of title case, so designs that mix the two break on translation. Second, sentence case reads as friendlier and less formal, which matches the conversational tone most modern interfaces aim for.
If you're writing product copy, the most useful thing you can do is pick one — sentence case is the safer modern default — and apply it religiously. Nothing makes an app feel half-finished faster than inconsistent capitalisation across nearby buttons.
The summary
Title case capitalises the major words. Sentence case capitalises only the first word and proper nouns. Title case feels traditional and editorial; sentence case feels modern and conversational. AP, Chicago, MLA, and APA disagree about prepositions and a handful of edge cases — pick one and apply it.
For most digital writing today, sentence case is the safer default. For traditional editorial contexts, title case still wins. Either way, the worst choice is inconsistency: pick a rule, write it down once, and stop deciding it on each heading.