What Is RGB?
RGB stands for Red, Green, Blue. It's a color model that defines any color by mixing three light values — one for red, one for green, and one for blue — each ranging from 0 to 255. A value of 0 means none of that channel; 255 means full intensity. Mixing all three at full intensity gives white (255, 255, 255); all at zero gives black (0, 0, 0).
In CSS, RGB colors are written as rgb(255, 87, 51)
or with transparency as rgba(255, 87, 51, 0.8).
Design tools like Figma, Sketch, and Adobe XD commonly report colors in RGB, as do most color pickers
built into operating systems.
What Is HEX?
HEX (hexadecimal) is a compact way to write the same RGB values using base-16 numbers instead of
base-10. Each RGB channel (0–255) is encoded as a two-character hex value (00–FF), and the three
channels are concatenated into a six-character string prefixed with a hash: #FF5733.
HEX is the dominant format in CSS, HTML, Tailwind CSS config files, design tokens, and most web design
tools. It's shorter to write than rgb() and easy to copy and paste as a single string. A three-character
shorthand also exists: #F83 expands to
#FF8833 by doubling each character.
RGB vs HEX: Side-by-Side Comparison
| Feature | RGB | HEX |
|---|---|---|
| Format | Decimal — rgb(255, 87, 51) | Hexadecimal — #FF5733 |
| CSS Support | Yes — rgb() and rgba() | Yes — #RRGGBB and shorthand #RGB |
| Transparency | Yes — rgba(r, g, b, alpha) | No (use rgba or 8-digit hex) |
| Human Readable | Channel values are intuitive | Compact, standard for web |
| Common In | Design tools, APIs, canvas | CSS files, HTML, Tailwind, design tokens |
| Color Accuracy | Identical to HEX | Identical to RGB |
| Copy/Paste Convenience | Longer to type | Short, single string |
When to Use HEX
HEX is the right choice for most web design and CSS work. Use it in stylesheets, Tailwind config files, design system tokens, and anywhere a single compact string is the expected format. Brand color guides almost always publish colors in HEX, and pasting a HEX code is faster than typing three separate numbers.
When to Use RGB
Use RGB when you need transparency — CSS's rgba()
function requires decimal channel values. Also use RGB when a canvas API, animation library, or other
tool expects numeric inputs rather than a hex string, or when a design tool outputs colors in RGB and
you need to match that format in your code.
How to Convert Between RGB and HEX
The math: each RGB channel (0–255) becomes a two-digit base-16 number. For rgb(255, 87, 51):
255 → FF, 87 → 57, 51 → 33 → #FF5733.
Going the other way, each two-character hex pair is converted from base-16 to base-10.
Our free converters handle this instantly: RGB to HEX and HEX to RGB — adjust sliders, type values directly, or use the color picker. No upload, no account.