HEX to RGB color conversion — understanding web color codes

Web colors can be written in HEX, RGB, or HSL format. Learn how each system works, how to convert between them, and which to use in CSS.

How computers represent color

Digital screens produce color by combining red, green, and blue light at different intensities. Each color channel has 256 possible values (0–255), giving 16,777,216 possible colors (256^3). This is why monitors are described as "24-bit color" — 8 bits per channel × 3 channels = 24 bits.

Understanding HEX color codes

A HEX color code like #FF5733 uses six hexadecimal digits. The first two (FF) are the red channel, the middle two (57) are green, and the last two (33) are blue. Each pair is a hexadecimal number from 00 to FF, which corresponds to decimal 0 to 255.

To convert FF to decimal: F = 15, so FF = (15 × 16) + 15 = 255. To convert 57: 5 = 5, 7 = 7, so (5 × 16) + 7 = 87.

So #FF5733 = rgb(255, 87, 51) — a shade of orange-red.

When to use each format in CSS

HEX: Most compact for static colors. Widely supported. Best for simple color values in CSS.

RGB: Easier to adjust manually. Supports alpha transparency with rgba(). Useful in JavaScript for color calculations.

HSL: Most intuitive for designers. Adjusting only L (lightness) creates tints and shades of the same color. Best for design systems and CSS custom property scales.

Converting between formats

The Color Converter on Smartweb.tools converts between all three formats instantly with a live preview. Enter a HEX code, use the color picker, or enter RGB values — the tool updates all formats simultaneously and lets you copy each one with a single click.