Every color on a screen is ultimately made of red, green, and blue light mixed at different intensities — hex, RGB, and HSL are just three different notations for describing that same mix. Knowing what each one actually represents makes it much easier to pick and adjust colors with intention instead of trial and error.
Hex Codes
A hex code like #2563EB packs the red, green, and blue values into six hexadecimal digits — two digits per channel, each ranging from 00 (none) to FF (full intensity, 255 in decimal). So #2563EB breaks down into 25 red, 63 green, and EB blue. Hex is compact and is the most common format in design tools and CSS, but the hexadecimal digits don't map intuitively to "brighter" or "more saturated" — you generally need a picker or converter to adjust a hex color deliberately.
RGB
RGB writes the same three channels as plain decimal numbers instead: rgb(37, 99, 235) is the exact same color as #2563EB, just with each channel written 0-255 instead of as two hex digits. RGB is arguably more readable than hex since the numbers are just base-10, but it shares the same core limitation — there's no single number you can nudge to make a color "lighter" or "more vivid" without recalculating all three channels together.
HSL
HSL takes a fundamentally different approach: instead of three color-channel intensities, it describes Hue (a position on the color wheel, 0-360°, where 0 is red, 120 is green, and 240 is blue), Saturation (0% is gray, 100% is fully vivid), and Lightness (0% is black, 100% is white, 50% is the "pure" version of the hue). This maps much more closely to how people actually think about adjusting a color — "make it a bit lighter" is just raising the Lightness number, with the hue staying exactly where it was.
hsl(224, 79%, 53%) is the same blue as #2563EB. Change only the Lightness to 70% and you get a visibly lighter version of the exact same blue — try doing that by eye in hex or RGB.
Which One Should You Use?
- Open the Color Converter to translate a color between hex, RGB, and HSL instantly.
- Use the Color Palette Generator if you need a set of coordinated colors rather than a single conversion.
- Reach for hex when writing final CSS values — it's the most universally supported, compact format.
- Reach for HSL while you're still designing and want to fine-tune lightness or saturation without losing the hue.
Picking a Color from an Image
Sometimes you don't have a color code to start from — just a photo or design mockup with a color you want to match exactly. An eyedropper tool zooms into the image so you can click the precise pixel, then reads that pixel's value back out in hex, RGB, or HSL, whichever format you need for your CSS or design tool.
FAQ
What does the # in a hex color code mean? The # is just a prefix that tells a program the following characters are a hexadecimal (base-16) color value, not a decimal number or another kind of code. It carries no color information itself — #FF0000 and FF0000 represent the same red, the # is simply the conventional marker for this format.
Why would I use HSL instead of RGB? HSL separates a color into Hue (the base color, 0-360°), Saturation (how vivid vs. gray), and Lightness (how close to black or white) — which maps to how humans actually think about adjusting color. To make an RGB color lighter you have to recalculate all three R, G, and B numbers together; in HSL you just increase the Lightness value and the hue stays exactly the same.
What is an 8-digit hex code (with alpha)? A standard hex code is 6 digits (RRGGBB), but an 8-digit hex code adds two more digits for alpha — transparency — making it RRGGBBAA. FF at the end means fully opaque, 00 means fully transparent, and values in between produce partial transparency, the same concept as the fourth value in rgba().
Do all three formats represent exactly the same colors? Yes — hex, RGB, and HSL are just three different ways of writing the same underlying color space; converting between them is a lossless, purely mathematical transformation. A color converter switching a value from one format to another doesn't change what color it is, only how it's written.