Color Converter
HEX, RGB, HSL and HSV from one value, with the WCAG contrast ratio against white and black.
Worked example
#4FD1C5 is rgb(79, 209, 197), hsl(172, 59%, 56%). Against white its contrast ratio is 1.9:1 — well below the 4.5:1 needed for body text, and the reason this colour works as an accent but not as a text colour.
HEX and RGB describe the same thing in different units; HSL describes it in the terms people actually think in — hue, saturation, lightness. Changing the lightness of an HSL colour keeps the hue, which is why design systems are usually authored in HSL and shipped in HEX.
Contrast is the measurement that matters
WCAG requires 4.5:1 for body text and 3:1 for large text. A colour that looks fine on your monitor can fail badly for someone reading on a phone in daylight, and the ratio is the only way to know without testing.