Color Converter & Contrast Checker

Which formats does it convert between?

HEX, RGB and HSL, in any direction. It also reports the pair's relative luminance and contrast ratio, so you can judge legibility without moving to another tool.

When is HSL more useful than HEX?

Whenever you are adjusting rather than specifying. HSL separates hue from saturation and lightness, so making a colour 10% lighter is one number instead of three unrelated ones. HEX is compact and universally understood; HSL is what you want while designing a scale.

Does converting HEX to HSL and back always return the same value?

Not always. HSL components are rounded to whole numbers here, and the sRGB cube does not map cleanly onto the HSL cylinder, so a round trip can land a digit away. The difference is imperceptible, but it means you should keep one canonical format in your tokens rather than converting back and forth.

Why does the tool show luminance as well?

Because lightness in HSL and perceived brightness are not the same thing. Two colours at L: 50% can look very different, since HSL lightness ignores how much more sensitive the eye is to green than to blue. Relative luminance applies that weighting, which is why it — not HSL lightness — is what accessibility standards use.

How is the contrast ratio computed?

(lighter + 0.05) / (darker + 0.05) on the relative luminances, the WCAG definition. If you are checking a text colour against a background specifically, the contrast checker reports the pass/fail levels alongside it.

Does it handle alpha or 8-digit hex?

No — it works on opaque colours. A colour with transparency has no fixed appearance until it is composited over something, so its contrast depends on what is behind it.

What about CMYK or Pantone?

Not supported, and the reason matters: those are print systems tied to inks and physical media. Converting a screen colour to CMYK meaningfully needs a colour profile and a target press, which is a different problem from arithmetic between screen formats.

Is my input sent anywhere?

No. All conversion happens in your browser.