Colour or Color: Which Spelling Should You Use?

This is not a spelling mistake in either direction, and treating it as one is the actual error. Colour and color are both standard English. Which you use depends on where your reader is, and the only thing that reads as careless is switching between them in the same document.

What most people get wrong is the history. The American spelling is widely assumed to be a modern shortcut, a lazy trimming of a proper British word. It is the other way round.

Which Spelling Should You Use?

Go by audience:

• Colour — the United Kingdom, Ireland, Australia, New Zealand, South Africa, India, and Canada.
• Color — the United States, and generally in international technical contexts where American conventions dominate, such as CSS and most programming languages.

Canada is the one that catches people out. Its proximity to the United States suggests it would follow American spelling, and for some words it does, but on the -our family it sides with Britain.

If you are writing for a genuinely international readership with no dominant market, colour is the marginally safer default: more English-speaking countries use it, even though American English has more speakers.

Where the Split Comes From

The divergence has an author, a date, and a motive.

Noah Webster published A Compendious Dictionary of the English Language in 1806, followed by his American Dictionary in 1828. He used both to promote deliberate spelling reforms: color for colour, center for centre, defense for defence, traveler for traveller.

His reach was not merely lexicographic. His spelling book of 1783 — the Blue-Backed Speller — sold in the millions and taught American schoolchildren for generations. A reform proposed in a dictionary can be ignored; a reform drilled into every child in the country cannot.

Not everything he wanted survived. He also pushed tung for tongue, wimmen for women, and ake for ache, and those went nowhere. The surviving American spellings are the fraction of his programme that happened to catch.

Meanwhile in England, Samuel Johnson's Dictionary of 1755 had already fixed colour with the U, and British printers followed him. The two authorities pulled in opposite directions, and the Atlantic did the rest.

The Surprise: The U Is the Newer Letter

Here is the part that reverses most people's assumption.

The Latin word is color. No U. It passed into Old French as colour, picking up the letter along the way, and Middle English borrowed the French form rather than the Latin one. Every English -our word in this family arrived by the same route: honour, favour, labour, neighbour.

So when Webster removed the U, he was not truncating a venerable spelling. He was returning to the classical form, and he said so explicitly. Whatever you think of his other proposals, this one has a better etymological case than the spelling it replaced.

And British English quietly agrees with him — in certain positions.

The U British Writers Drop Without Noticing

Before several suffixes, the U vanishes in British English too:

British writers write	Not
coloration	colouration
colorimetric	colourimetric
honorary, honorific	honourary
laborious	labourious
vigorous, invigorate	vigourous

A British writer can produce colour and coloration in the same paragraph without blinking. The U is not welded to the root; it survives in the plain noun and disappears when a Latin-derived suffix arrives.

This is worth knowing for a practical reason: if you write British English and a spellchecker flags colouration, the spellchecker is right.

Colour and Color in Real Sentences

British:

• "The colour of the walls was wrong, but the coloration of the fabric matched."
• "She has an eye for colour and a background in colorimetric analysis."

American:

• "The color scheme runs through every page."
• "Color the shape before you cut it out."

Both, unchanged: watercolour / watercolor follows the same regional rule, and so do colourful / colorful. The suffix -ful is English rather than Latin, so it does not trigger the drop.

Colour vs Color: Side by Side

	Colour	Color
Region	UK, Ireland, Australia, NZ, South Africa, India, Canada	United States
Origin	Old French colour	Latin color — the older form
Fixed by	Johnson's Dictionary, 1755	Webster's dictionaries, 1806 and 1828
Before Latin suffixes	drops the U (coloration)	unchanged
In code (CSS, most languages)	not used	standard

A Memory Hook That Sticks

U is for United Kingdom. The U stays where the country has one in its name. It is crude, it has nothing to do with etymology, and it works every time.

For the second half — the suffix rule — remember that the U is a passenger, not a resident. It rides along in colour and gets off before -ation.

Related Spelling Mixups

The same transatlantic logic governs gray vs grey, where the split runs the other way round from what most people expect, and totalling vs totaling, where the difference is a doubled consonant rather than a dropped vowel. Both belong to the same reform programme, and both are covered in the guide to commonly confused words.

Conclusion

Neither spelling is a mistake, and the American one is not a corruption of the British one — if anything, it is the older shape of the word, restored on purpose by a man who thought a new country should not inherit French spelling conventions along with everything else.

Choose by audience. Keep it consistent. And if you write British English, remember that you already drop the U yourself, roughly once a paragraph, without ever having decided to.