Color Code Converters: HEX, RGB, HSL & CMYK Explained
Every color on a screen or in a print job has to be described in a format some piece of software understands — and there are several competing formats in everyday use. A designer might hand you a color as #FF5733, a CSS stylesheet might define it as rgb(255, 87, 51), a print shop needs it as a CMYK percentage mix, and a design tool might show it as HSL for easier hue adjustment. None of these are "more correct" than the others — they're just different ways of describing the same color for different purposes, and converting between them is one of the most common small tasks in web design and development.
This guide explains what each color format actually represents, how the conversion math works, and links to every free color tool on this site.
#FF5733) and RGB (rgb(255,87,51)) describe the exact same color — HEX is just RGB written in base-16 instead of base-10. HSL describes color by hue, saturation and lightness instead of red/green/blue mixing, which makes it more intuitive for humans adjusting a color by eye. CMYK is used specifically for print, where colors are mixed from cyan, magenta, yellow and black ink rather than emitted as light.The Four Color Formats, Explained
HEX — The Web Standard
HEX (hexadecimal) codes are six-digit values like #FF5733, where each pair of digits represents the intensity of red, green, and blue on a 00-FF (0-255) scale. It's the format used almost everywhere in HTML and CSS (color: #FF5733;), and the one most design tools display by default because it's compact — six characters instead of RGB's longer rgb(255, 87, 51) syntax.
RGB — Red, Green, Blue
RGB describes a color as three numbers from 0 to 255, one each for red, green, and blue light intensity. It's the same underlying data as HEX, just written in decimal instead of hexadecimal — which is why HEX to RGB and RGB to HEX conversion is pure arithmetic with no approximation or data loss in either direction.
HSL — Hue, Saturation, Lightness
HSL describes color the way a person intuitively thinks about it: Hue (a 0-360° position on the color wheel), Saturation (how vivid vs. gray the color is, 0-100%), and Lightness (how close to black or white, 0-100%). It's the easiest format to adjust by hand — sliding the hue keeps the same vividness and brightness while shifting the actual color, which RGB and HEX can't do without recalculating all three channels.
CMYK — The Print Format
CMYK stands for Cyan, Magenta, Yellow, and Key (black), expressed as percentages. Unlike RGB/HEX/HSL, which describe light emitted from a screen, CMYK describes ink absorbed on paper — mixing more ink makes a color darker, the opposite of mixing more light. This is why a color that looks vivid on screen (RGB) can look duller when printed (CMYK); the two color spaces don't map onto each other perfectly, which is a common source of "why doesn't my printed color match my screen" frustration for designers.
The Same Color, Four Ways
| Swatch | HEX | RGB | HSL | Common Name |
|---|---|---|---|---|
| #FF5733 | rgb(255, 87, 51) | hsl(11, 100%, 60%) | Orange-red | |
| #1A4B8C | rgb(26, 75, 140) | hsl(213, 69%, 33%) | Deep blue | |
| #00AF66 | rgb(0, 175, 102) | hsl(155, 100%, 34%) | Emerald green | |
| #F5A623 | rgb(245, 166, 35) | hsl(36, 90%, 55%) | Amber |
How HEX-to-RGB Conversion Actually Works
Split the six-digit HEX code into three pairs of two digits, then convert each pair from hexadecimal to decimal. For #FF5733:
- FF (hex) = 255 (decimal) → Red
- 57 (hex) = 87 (decimal) → Green
- 33 (hex) = 51 (decimal) → Blue
Giving rgb(255, 87, 51). The reverse (RGB to HEX) just runs the same math backward — converting each 0-255 decimal value to its two-digit hex equivalent and concatenating them.
rgba() for transparency), and vice versa — which is why having both directions available as instant, free tools saves real time compared to doing the hex math by hand.All Color Conversion Tools
Frequently Asked Questions
Is HEX or RGB the "real" color format?
Neither — they describe the exact same color, just in different number bases (RGB in decimal, HEX in hexadecimal). Converting between them never loses information or changes the actual color; it's purely a notation difference, unlike converting to CMYK.
Why does a color look different when printed than it does on screen?
Screens create color by emitting red, green and blue light (RGB), while printers create color by layering cyan, magenta, yellow and black ink that absorbs light (CMYK). The two color spaces cover different ranges of possible colors, so an RGB-to-CMYK conversion is always an approximation — some vivid screen colors simply can't be reproduced exactly in ink.
What does the # symbol mean in a HEX color code?
It's just a syntax marker telling CSS/HTML "the following six characters are a hexadecimal color value" rather than a variable name or keyword. The # itself carries no color information — #FF5733 and FF5733 represent the identical color.
Why does HSL make it easier to create a color palette?
Because Hue, Saturation and Lightness are independent sliders that map to how humans actually perceive color differences. Keeping Saturation and Lightness fixed while only changing Hue produces a smooth, evenly-toned set of colors — try doing that by adjusting RGB's three interdependent channels and the results look inconsistent.
Can every RGB color be represented exactly in HEX?
Yes. Since HEX is just RGB written in base-16, every one of the 16,777,216 possible RGB combinations (256³) has an exact six-digit HEX equivalent with no rounding, unlike the RGB-to-CMYK conversion which is only an approximation.
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