Tool
What the XYZ Color Converter does
XYZ Color Converter: converts CIE XYZ, HEX and RGB from Pick a colour.
From Pick a colour, this tool derives CIE XYZ, HEX and RGB. Edit a field and the answer updates in place.
Typical users are anyone checking a colour for legibility. Contrast failures are the most common accessibility problem on the web, and the easiest to fix.
There is no back end here. The calculation runs where you are sitting, not on a server somewhere.
The method, a field-by-field reference and a worked example built from the defaults are all on this page.
What do the XYZ Color Converter fields mean?
The XYZ Color Converter uses 1 input. Each input has a default that makes sense on its own, so a partial edit still gives a valid result.
| Field | What to enter | Default |
|---|---|---|
| Pick a colour | optional | #2563eb |
How does the XYZ Color Converter work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same conversion.
The tool refuses to guess: if a value is missing or impossible, it says so.
What a typical run looks like
You provide: Pick a colour
What happens: the file is read into memory by your browser, processed locally, and offered back as a download. It is never uploaded.
You get back: a download link for the new file and a short note on what changed.
Timing comes down to your own hardware, and the practical size limit is how much memory the browser will hand the tab.
CIE XYZ: the reference space
CIE XYZ, defined in 1931, is the foundation every other colour space is ultimately defined against. It is based on measurements of human colour perception rather than on any device.
| X | mixture of cone responses | roughly red-green |
|---|---|---|
| Y | luminance | matches perceived brightness |
| Z | short-wavelength response | roughly blue |
| Defined | CIE, 1931 | from colour-matching experiments |
Worth knowing
- Y is deliberately defined as luminance, which is why the WCAG relative luminance formula is essentially an XYZ Y calculation.
- XYZ is the usual intermediate step: converting sRGB to Lab goes via XYZ, because both are defined in relation to it.
- A white point must be specified: D65 for sRGB and most screen work, D50 for print. Using the wrong one shifts every converted colour.
- XYZ can represent imaginary colours: mathematically valid coordinates that correspond to no physically realisable light.
How to use it
- Fill in Pick a colour.
- Type a value and the answer is already there by the time you stop.
- The panel reports CIE XYZ, HEX, RGB, HSL and CMYK.
- Copy Link is the quickest way to send the exact scenario to someone else.
What this tool does not do
- Conversions between colour spaces with different gamuts are approximate at the edges.
- Colours render differently across displays; the values are exact but the appearance is not guaranteed.
- Assumptions built into the method are stated above, but they are still assumptions.
Frequently asked questions
Pick a colour, nothing else. Nothing starts empty, which means a single edit is enough to get a meaningful answer.
No record is kept. We never receive what you type, so there is nothing on our side to retain.
Nothing at all. There is no registration, no paywall and no per-use quota.
The logic is straightforward and testable; the worked example above uses the tool’s own defaults so you can verify it yourself.