Is it spelled grey or gray, and do they mean different colours?

One Old English word, two modern spellings

The word goes back to Old English grǣg, with a Mercian form grei, and has relatives across the Germanic languages; the French, Spanish and Italian words for the colour were borrowed from Germanic too. The etymology source used here dates the distinction, grey for British English and gray for American, to the twentieth century, which implies that before then the spelling was not divided along national lines. Nothing about meaning ever attached to the difference. Claims that 'gray' is a cooler or bluer colour than 'grey', or that one is a mixture and the other a neutral, have no basis in the history of the word: they are attempts to make a spelling difference mean something.

What CSS does with the two spellings

CSS Color 4 lists seven keywords containing the word and defines each twice, once with each spelling: gray and grey, darkgray and darkgrey, dimgray and dimgrey, lightgray and lightgrey, slategray and slategrey, darkslategray and darkslategrey, lightslategray and lightslategrey. Within each pair the values are identical, so a stylesheet may use either. That tolerance stops at the standard. A design-token file, a product database or a spreadsheet of paint colours treats 'grey' and 'gray' as different strings, and a search or filter written for one spelling silently misses the other. The colour is the same; the data is not, and that is where the two spellings cause real faults.

The keyword called dark that is lighter

Ordered by lightness, the CSS greys do not follow their names. Plain gray is the mid-point of sRGB code values, with an OKLCH lightness of 0.60. Darkgray has 0.73: it is the lighter of the two. The keyword that is actually darker than gray is dimgray, at 0.52. The three slate greys are not neutral at all; slategray has a chroma of 0.031 at a blue hue, just outside the lexicon's grey region, whose chroma limit is 0.03. The table below gives the full set. Anyone building a neutral scale from these names will get steps in the wrong order, and a faint blue cast in some of them.

Where grey begins and ends in the lexicon

Grey is a basic colour term defined by what it lacks. The lexicon's region allows any hue, a chroma of at most 0.03, and a lightness of 0.40–0.85. Above that it becomes silver or an off-white, and 67% of silver's grid colours are also inside grey; below it, charcoal and then black. The published values agree closely for once: CSS gives the exact mid-grey and the crowd survey's grey (#929591) is slightly lighter, at 0.67, with a trace of green too small to see. Where usage does vary is in how much hue a grey may have before it needs another name. A warm grey or a blue-grey is still a grey to most speakers, well past the chroma at which the lexicon stops.

Which spelling to use, and where it matters

In prose, follow the variety of English you are writing: grey for British English, gray for American, and the local style guide for any other variety. Proper names keep their own spelling whatever the surrounding text does, so a product called 'Dove Gray' stays that way in a British catalogue. In code and data, pick one spelling for identifiers and keep to it, and make any search, filter or import step treat the two as the same word. Colourwise writes 'grey' throughout, and its lexicon lists 'gray' as an alias of the same term. When exchanging colour names between British and American teams, the spelling is the least of the differences to check: the same word can mean different colours, and that is what a value settles.

The data

What goes wrong, and what to do

What the evidence says

Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.

• StandardStrong evidence

  CSS Color Level 4 defines seven pairs of keywords that differ only in the spelling gray or grey, each pair with an identical value.

  Source: CSS Color Module Level 4

• FactModerate evidence

  The word descends from Old English grǣg, and the spelling distinction between British grey and American gray developed in the 20th century.

  Caveat: Summarised from a compiled etymology reference, which gives the century and not a more precise date.

  Source: Online Etymology Dictionary

• Colourwise analysisStrong evidence

  The CSS keyword darkgray (#a9a9a9) has an OKLCH lightness of 0.73, higher than gray (#808080) at 0.60; dimgray (#696969) is the darker one at 0.52.

  Based on: OKLCH lightness computed by Colourwise from the keyword values in CSS Color 4.

  Source: CSS Color Module Level 4

• Colourwise interpretationModerate evidence

  The two spellings name the same colour; no difference in meaning is attached to them in the word's recorded history or in the CSS standard.

  Based on: The etymology source records a single word with regional spellings, and CSS Color 4 assigns identical values to every gray/grey keyword pair.

Related questions

Is gray a different shade from grey?

No. They are two spellings of one word for one colour. Any difference you see between a product labelled 'gray' and one labelled 'grey' comes from the makers' choices of colour, not from the spelling.

Why is darkgray lighter than gray in CSS?

The specification does not say. It defines gray as #808080 and darkgray as #a9a9a9 as two independent fixed values, so the names cannot be read as steps on one scale. Use dimgray for a keyword darker than gray.

Do browsers accept both grey and gray in CSS?

Yes. CSS Color 4 defines every grey keyword under both spellings with the same value, so 'grey' and 'gray', or 'lightgrey' and 'lightgray', are interchangeable in a stylesheet.

Related topics

Go further

Sources

• CSS Color Module Level 4 — W3C (World Wide Web Consortium) (Official standard or government)
• Online Etymology Dictionary — Douglas Harper (Reference work)
• Colourwise editorial synthesis — Colourwise (Colourwise editorial)
• Color survey results, and the rgb.txt list of the 954 most common colour names — xkcd (Randall Munroe) (Reference work)

Reviewed 1 October 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.