Capital Letters: The Rules Beyond the Obvious
Nobody struggles with the start of a sentence. The errors cluster in a narrow band of cases, and almost all of them come from the same instinct: capitalising a word because it feels significant.
The principle underneath
English capitalises proper nouns — the specific name of a particular thing. It does not capitalise common nouns, which name a category.
Importance has nothing to do with it. The president is a more important person than Steve, and only one of those is capitalised.
Job titles
Capitalised directly before a name; lower case everywhere else.
- President Lincoln — part of the name.
- Abraham Lincoln, the president — a description.
- The chief executive announced — a role.
- Chief Executive Maria Hall announced — a title.
Business writing breaks this constantly — please contact our Head of Marketing — because organisations feel their titles are important. They are common nouns.
Seasons, directions, decades
Seasons are lower case. spring, summer, autumn, winter. Days and months are capitalised; seasons are not, which is inconsistent and simply how it is.
Directions are lower case; regions are capitalised. Drive north for an hour against she grew up in the North. The test: a direction is where you are going, a region is a place with an identity.
Decades and centuries are lower case. the nineties, the twentieth century.
Family words
Capitalised when used as a name; lower case with a possessive:
- I asked Mum. — used as her name.
- I asked my mum. — a description.
- Happy birthday, Grandad! against his grandad taught him.
The test: could you substitute the person’s actual name? If yes, capitalise.
Titles of works
Two conventions:
- Title case — capitalise the main words. Articles, short prepositions and conjunctions stay lower case unless first or last: The Old Man and the Sea.
- Sentence case — capitalise only the first word and proper nouns: The old man and the sea. Standard in academic references and increasingly common for headlines.
Where the instinct goes wrong
Capitalising for emphasis is the most common error in professional writing:
- Wrong: Please submit your Application before the Deadline.
- Wrong: Our Company values Innovation and Integrity.
These are common nouns dressed up. The capital adds no meaning, and to a reader who knows the convention it reads as marketing rather than information.
Exception worth knowing: contracts and formal agreements capitalise Defined Terms deliberately, to signal that a word has a specific meaning set out elsewhere in the document. That is a genuine convention with a purpose — and it is the only one of its kind.
Checked against Merriam-Webster, the Chicago Manual of Style and the AP Stylebook. Spotted an error? Tell us — see our editorial policy.
