The hsl() functional notation expresses a given color according to its hue, saturation, and lightness components. An optional alpha component represents the color's transparency.


CSS Colors Level 4 made some changes to hsl(). In browsers that support the standard hsla() is an alias for hsl(), they accept the same parameters and behave the same way.

The Level 4 specification also allows for space-separated in addition to comma-separated values.


hsl(100, 100%, 50%) /* #5f0 */
hsl(235, 100%, 50%, .5) /* #0015ff with 50% opacity */
hsl(235 100% 50%); /* CSS Colors 4 space-separated values */


Functional notation: hsl[a](H, S, L[, A])
H (hue) is an <angle> of the color circle given in degs, rads, grads, or turns in CSS Color Module Level 4. When written as a unitless <number>, it is interpreted as degrees, as specified in CSS Color Module Level 3. By definition, red=0deg=360deg, with the other colors spread around the circle, so green=120deg, blue=240deg, etc. As an <angle>, it implicitly wraps around such that -120deg=240deg, 480deg=120deg, -1turn=1turn, etc.
S (saturation) and L (lightness) are percentages. 100% saturation is completely saturated, while 0% is completely unsaturated (gray). 100% lightness is white, 0% lightness is black, and 50% lightness is “normal.”
A (alpha) can be a <number> between 0 and 1, or a <percentage>, where the number 1 corresponds to 100% (full opacity).
Functional notation: hsl[a](H S L[ / A])
CSS Colors Level 4 adds support for space-separated values in the functional notation.

Browser compatibility

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Space-separated values

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Accepts alpha value

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