Which colour names are supported?

All 148 CSS named colours from the CSS Color Module (from aliceblue to yellowgreen, including rebeccapurple) plus hex codes in 3, 4, 6, and 8 digit forms and rgb()/rgba() values. Matching is case-insensitive.

How is OKLCH calculated?

The sRGB value is linearised, converted to the OKLab colour space via Bjorn Ottosson's published matrices, then expressed as lightness, chroma, and hue. OKLCH gives perceptually even lightness, which is why it is used for accessible palette generation.

What is the difference between HSL and HSV?

Both use the same hue angle, but HSL describes a colour by hue, saturation, and lightness (50% lightness is the pure hue), while HSV uses value (100% value plus full saturation is the pure hue). They are different geometric models of the same RGB cube.

Why does LAB use a D65 white point?

CIELAB is defined relative to a reference white. sRGB is specified for the D65 illuminant, so the converter uses the D65 white point to keep the LAB values consistent with how the colour appears on a standard screen.

Does this run online?

No. The colour table and all conversion maths are bundled into the page and run in your browser. Nothing is uploaded, so you can use it offline once the page has loaded.

Colour Name to Hex / RGBA Converter

The Colour Name to Hex / RGBA Converter resolves any CSS named colour, hex code, or rgb() value to a canonical hex and then expresses it across six colour spaces: hex, RGB, HSL, HSV, CIELAB, and OKLCH. Named colours like rebeccapurple are convenient in code but opaque when you need their exact channel values for a contrast check or to generate a theme. This tool gives you every representation at once, computed locally with the standard formulas.

How it works

Resolve to RGB. A named colour is looked up in the bundled 148-entry CSS colour table; a hex code is parsed (3, 4, 6, or 8 digit); an rgb()/rgba() value is read directly. The result is an 8-bit RGB triple plus alpha.
HSL and HSV. Both are derived from RGB using the standard hexcone formulas — they share the same hue angle but differ in how they express brightness.
CIELAB. RGB is gamma-expanded to linear sRGB, multiplied by the sRGB-to-XYZ matrix under the D65 white point, then transformed to L*a*b* with the CIE cube-root function.
OKLCH. Linear sRGB is converted to OKLab via Bjorn Ottosson’s published matrices and cube-root step, then a/b are turned into chroma and hue to give OKLCH — the perceptually uniform space modern palette tools rely on.

Tips and notes

OKLCH lightness is perceptual, so two colours with the same L look equally bright; that is why it is preferred for building accessible light/dark palettes.
For contrast ratios you only need the sRGB channels — copy the RGB or hex value into a WCAG contrast tool.
An 8-digit hex (#3b82f6cc) carries an alpha channel; the converter shows the alpha separately so you can keep or drop it.