Quick answer: Capitalize the first word of every sentence, the pronoun I, and all proper nouns — the specific names of people, places, brands, organizations, days, months, languages and nationalities. For a title or heading, use title case: capitalize the first word, the last word and every important word in between, but keep articles (a, an, the), coordinating conjunctions (and, but, or) and short prepositions lowercase. Do not capitalize common nouns, seasons or ordinary words simply for emphasis.
The Three Rules That Never Change
Almost all of English capitalization comes down to three reliable rules:
- Start every sentence with a capital letter. This includes the first word of a full-sentence quotation: She said, "The meeting is over."
- Always capitalize the pronoun I. English is unusual here — I is capitalized wherever it lands in the sentence: My sister and I left early.
- Capitalize proper nouns. A proper noun is the specific name of one particular person, place or thing. A common noun is the general word for a type of thing, and it stays lowercase.
That proper-versus-common distinction does most of the heavy lifting:
- ✓ We drove through a city in France. — ✓ We drove through Paris.
- ✓ My favourite month is warm. — ✓ My favourite month is July.
- ✗ I love the ocean in the Summer. → ✓ I love the ocean in the summer.
Which Words Are Proper Nouns?
Capitalize each of the following, because each one names something specific:
- People and titles before a name: Marie Curie, Dr. Patel, President Lincoln, Aunt Rosa.
- Places: Tokyo, the Nile, Mount Everest, Oxford Street, the Sahara.
- Brands, companies and products: Google, Coca-Cola, the iPhone, Netflix.
- Days, months and holidays: Monday, March, Diwali, Thanksgiving — but not the seasons.
- Languages, nationalities and religions: English, Japanese, Spanish, Buddhism, a Canadian passport.
- Named periods and events: the Renaissance, World War II, the Great Depression.
- Titles of works: Hamlet, The Godfather, The New York Times.
Proper adjectives — adjectives made from proper nouns — stay capitalized too: French wine, a Shakespearean plot, Victorian architecture.
Title Case: How to Capitalize a Heading
Title case (also called headline style) is the pattern used for book titles, article headings and film names. The rules:
- Always capitalize the first and last word, whatever they happen to be.
- Capitalize all "major" words: nouns, pronouns, verbs, adjectives and adverbs.
- Keep the small joining words lowercase: articles (a, an, the), coordinating conjunctions (and, but, or, nor, for) and short prepositions (at, by, in, of, on, to, up).
Examples:
- ✓ The Lord of the Rings — ✗ The Lord Of The Rings
- ✓ A Tale of Two Cities — ✗ A Tale Of Two Cities
- ✓ How to Train Your Dragon (the infinitive to stays lowercase) — ✗ How To Train Your Dragon
The one genuine grey area is longer prepositions. The Chicago Manual of Style lowercases every preposition, so it writes A Room with a View. AP style capitalizes any word of four or more letters, so it writes A Room With a View. Both are correct — just pick one style and stay consistent within a piece of writing.
Sentence Case: The Simpler Modern Style
Many websites, apps and British newspapers now prefer sentence case for headings — capitalize only the first word and any proper nouns, exactly like a normal sentence: How to train your dragon. It is cleaner and much harder to get wrong, which is why so much digital writing has adopted it.
The Most Common Over-Capitalizing Mistakes
Modern English capitalizes less than most people think. These are the errors that show up most often:
- Seasons. ✗ See you in the Autumn. → ✓ See you in the autumn. (Capitalize only inside a name: the Summer Olympics.)
- Compass directions. ✗ Drive North for a mile. → ✓ Drive north for a mile. But capitalize a named region: She grew up in the South.
- Job titles standing alone. ✓ We met President Roosevelt. but ✗ We met the President. → ✓ We met the president. Capitalize a title only when it sits directly before the name.
- Family words with a possessive. ✓ I called Mom. (used as a name) but ✗ I called my Mom. → ✓ I called my mom.
- School subjects. ✗ I'm studying Biology and History. → ✓ I'm studying biology and history. (Languages stay capital — English — and so do named courses — Biology 101.)
- Emphasis. ✗ This is a Very Important Decision. → ✓ This is a very important decision. Use bold or italics for emphasis, never capitals.
- Random "important" nouns. ✗ Please email the Report to the Manager. → ✓ Please email the report to the manager.
- The internet. ✗ the Internet → ✓ the internet. Major style guides made internet and web lowercase back in 2016.
Tricky Cases and Real Exceptions
- After a colon. Usually keep the next word lowercase: She had one goal: to win. Capitalize only if a proper noun follows — or, in US style, if a complete sentence follows (see below).
- Eponyms that went generic. Words born from names but now everyday and lowercase: a herculean effort, a quixotic plan, a diesel engine, a sandwich, to boycott.
- Brand names with unusual casing. Follow the brand: iPhone, eBay, adidas. If one would open a sentence, it is cleaner to reword than to start the sentence with a lowercase letter.
- Quotation fragments. Capitalize a quoted full sentence, but not a quoted fragment: He called it "the worst idea ever."
- Hyphenated words in titles. Capitalize both meaningful parts: A Well-Written Essay, The Twenty-First Century.
A Memory Trick That Works
For proper nouns, ask yourself: "Could I point to this exact thing on a map, a calendar or an ID card?" A country, a weekday, a person's name — yes, so capitalize. A general word like river, month or manager — no, so keep it lowercase. For titles, remember the shorthand: capitalize the big words, keep the little glue words small — but never lowercase the first or last word.
US vs UK: Do the Rules Differ?
Far less than people assume — sentence starts, proper nouns and title case work the same on both sides of the Atlantic. Two genuine differences are worth knowing:
- After a colon. American guides (especially APA) often capitalize a complete sentence that follows a colon: He was certain: The plan would fail. British style keeps it lowercase: He was certain: the plan would fail.
- Headline style. US publications lean toward title case for headlines, while many British outlets (such as The Guardian and the BBC) use sentence case. Both are house-style choices, not grammar rules.
Frequently Asked Questions
Do you capitalize job titles?
Capitalize a job title when it comes directly before a person's name, because it acts as part of that name: Prime Minister Attlee, Professor Diaz, Detective Morgan. When the title stands alone or follows the name, keep it lowercase: the prime minister spoke; Diaz, a professor of law, agreed. This rule holds in both US and UK style.
Should you capitalize the first word after a colon?
Usually no — keep it lowercase: We had one rule: stay quiet. Capitalize only if a proper noun follows, or, in American style, if the colon introduces a complete sentence (APA and many US guides do this). British English keeps it lowercase either way. When in doubt, lowercase is the safer, more widely accepted choice.
Are the seasons capitalized?
No. Spring, summer, autumn, fall and winter are common nouns and stay lowercase: I love summer evenings. Capitalize a season only when it forms part of a proper name, such as the Summer Olympics or the Winter Formal, or when it is personified in poetry. Writing 'in the Winter' is one of the most common capitalization errors.
What words should not be capitalized in a title?
In title case, keep three groups lowercase unless they are the first or last word: articles (a, an, the), coordinating conjunctions (and, but, or, nor, for) and short prepositions (of, in, on, to, at, by). So it is The Grapes of Wrath, not The Grapes Of Wrath. Everything else — nouns, verbs, adjectives, adverbs — is capitalized.
Is it 'Internet' or 'internet'?
Lowercase internet is now standard. Major style guides, including the AP Stylebook and Chicago, changed Internet to internet in 2016, and web is lowercase too. Capitalize it only when it begins a sentence or appears inside an official name. So write: I found it on the internet — not on the Internet.
