A hex color code is a 6-character hexadecimal representation of an RGB color, prefixed with #. Each pair of characters represents the intensity of Red, Green, and Blue channels, ranging from 00 (0, no intensity) to FF (255, full intensity). For example, #FF0000 means pure red — maximum red, zero green, zero blue. Short 3-digit codes like #F00 are shorthand where each digit is doubled: #F00 = #FF0000.

This tool compares your input hex color against a database of 156 named colors (CSS standard names + X11 colors) using the Euclidean distance in RGB color space. The distance is calculated as: √((R₁-R₂)² + (G₁-G₂)² + (B₁-B₂)²). The color with the smallest distance is the closest match. We then convert this distance into a similarity percentage, where 100% means an exact match and lower percentages indicate increasing visual difference. The top 5 closest colors are displayed for your reference.

CSS named colors are human-readable color keywords like tomato, dodgerblue, or goldenrod that browsers recognize natively. There are 148 standard CSS color names (including transparent). Using named colors in your stylesheets makes code more readable and maintainable — background: coral; is often clearer than background: #FF7F50;. They're fully supported across all modern browsers and are great for rapid prototyping, theming, and collaborative projects where readability matters.

Hue is the attribute of color that defines its position on the color wheel — essentially, what we commonly call "color" (red, blue, green, etc.). In the HSL color model, hue is measured in degrees from 0° to 360°: 0°/360° is red, 60° is yellow, 120° is green, 180° is cyan, 240° is blue, and 300° is magenta. This tool identifies your color's hue angle and categorizes it into one of 12 segments (e.g., Warm Red, Orange, Yellow, Lime Green, Cool Cyan, Deep Blue, Violet, etc.), helping you understand where your color sits on the spectrum.

The similarity percentage indicates how visually close your input color is to the matched named color. 100% = exact match, 95%+ = nearly identical (barely perceptible difference), 85–95% = very close (subtle shade variation), 70–85% = moderately close (noticeable but in the same color family), and below 70% = loosely related. The Euclidean RGB distance works well for most practical purposes, though it doesn't perfectly account for human visual perception (where CIE Lab and Delta-E metrics excel). For design work requiring perceptual accuracy, consider using a Delta-E based tool. This tool is ideal for quick lookups, CSS prototyping, and discovering color name alternatives.

Yes! This tool automatically expands 3-digit shorthand hex codes. A 3-digit code like #F80 is expanded to #FF8800 by doubling each digit. This shorthand is valid in CSS and HTML and represents the same color in a more compact form. Simply type or paste the 3-digit code (with or without the # prefix), and the tool will normalize it to the full 6-digit representation for accurate matching.