gdt.colour

Colour Tools

Pick colours, convert between formats, check WCAG contrast and generate palettes.

No account needed — runs in your browser open Colour Tools
Picker, conversions and a contrast check side by side.
Picker, conversions and a contrast check side by side.

What it does

  • A colour picker with the value shown in HEX, RGB, HSL and more, and one-click copy.
  • Convert any colour between formats by pasting it in.
  • Contrast checker for text against a background, graded against WCAG AA and AAA.
  • Palette generator: complementary, analogous, triadic and shades from a base colour.

Who it's for

Designers and developers who need a quick answer without opening a design app.

Your data

Everything happens in your browser. Nothing you type or upload is sent to the server, and nothing is stored unless the tool says it saves to your browser.