They are the same word with two spellings: colored is standard in the United States, coloured in Britain, Ireland, Australia and most of the Commonwealth. "Colored pencils" and "coloured pencils" mean exactly the same thing. Applied to people, however, both spellings are dated and offensive in the US and UK.
The core difference
There is no difference in meaning, only in nationality of spelling. American English dropped the u from a family of words borrowed through French — colour, honour, favour, labour — and Britain kept it. Both are fully correct within their own conventions, and neither is a mistake.
Which to use
- Writing for a US audience, or in a US publication: colored, color, coloring, colorful.
- Writing for a UK, Irish, Australian, New Zealand, South African or Indian audience: coloured, colour, colouring, colourful.
- Canada generally follows the British u in colour, despite following American practice in other spellings.
The rule that matters most is consistency. Pick one convention for a document and hold it — a page that mixes colour and color reads as careless regardless of which side you favour.
The test
Ask who is reading. If your reader is American, drop the u; otherwise keep it. If you are unsure, check the surrounding words: if the text already says organize and center, it is American, so write colored. If it says organise and centre, write coloured.
The part that actually matters
Used of people, this word is not a spelling question but a historical one, and it needs stating plainly. In the United States, colored was the polite term of an earlier era, was superseded first by Black and then by African American, and is now offensive. Its only surviving use is in the name of the NAACP, which retains its historical title. In Britain, coloured followed a similar path and is likewise offensive today.
Note that person of colour and people of colour are not the same expression and are not affected by this. They are current, accepted terms, and the difference is not merely cosmetic — they were adopted deliberately as a self-chosen alternative.
One important exception: in South Africa, Coloured is a recognised ethnic designation with a specific meaning, used in the census, in official statistics and by members of the community themselves. It is capitalised there and is not an insult in that context. Writers outside South Africa should not borrow it.
Everything else
For objects, materials and descriptions the word is entirely ordinary in either spelling: coloured glass, colour-coded folders, a brightly coloured jumper, colored contact lenses. No sensitivity attaches to any of these.
Frequently Asked Questions
Is colored or coloured correct?
Both. Colored is standard American spelling; coloured is standard in Britain and most of the Commonwealth. Choose by audience and stay consistent within a document.
Is it ever acceptable to describe a person as coloured?
In the US and UK, no — the term is dated and offensive. In South Africa, Coloured is a recognised ethnic designation used officially and by the community itself, but writers elsewhere should not adopt it.
Is "person of colour" the same term?
No. It is a distinct, current expression that was adopted deliberately, and it is widely accepted. It is unaffected by the problems with the older word.