Quick Comparison
| Feature | HEX | RGB |
|---|---|---|
| Format | #RRGGBB (6 hex digits) | rgb(R, G, B) |
| Length | 7 chars including # | 12–18 chars typically |
| Channels | 3 implicit (R, G, B) | 3 explicit |
| Alpha support | 8-digit #RRGGBBAA | rgba(R, G, B, A) |
| Easy in JS math | Awkward — need parsing | Native — values are numbers |
| Best for | CSS, design tools, brand specs | JS animations, opacity work |
What Are HEX Colors?
A HEX colour is a 6-digit hexadecimal number prefixed with #. Each pair of digits maps to a 0–255 value for one channel:
#FF5733
↑↑↑↑↑↑
RR GG BB
FF = 255 (red)
57 = 87 (green)
33 = 51 (blue)The first two digits encode red, the next two green, the last two blue. Hex codes are case-insensitive — #FF5733 and #ff5733 are identical.
What Is RGB?
RGB describes the same colour using three explicit decimal numbers:
rgb(255, 87, 51)
255 = red channel
87 = green channel
51 = blue channelEach channel ranges from 0 (none of that colour) to 255 (maximum). The total possible combinations are 256³ = roughly 16.7 million colours.
Same Color in Both Formats
The orange used in the ConvertDox brand can be written either way:
When to Use HEX
- CSS and HTML — shorter to type than rgb().
- Design tools — Figma, Sketch, Adobe XD all default to hex output.
- Brand specs and style guides — every brand book uses hex.
- Email templates — universally supported across email clients.
- Quick reference and code reviews — easier to memorize and recognise.
When to Use RGB
- CSS animations or transitions involving partial transparency.
- JavaScript colour manipulation — channels are already numbers, no parsing needed.
- Photo editing software sliders work in RGB.
- Programmatic colour generation — interpolating between two colours is straightforward.
- When alpha (opacity) matters — rgba() is more readable than 8-digit hex for many developers.
RGBA and HEXA (Alpha Channel Variants)
Both formats have alpha-channel siblings that add opacity.
/* 50% opaque orange */
rgba(232, 93, 4, 0.5)
#E85D0480 // last 80 ≈ 50% opacityThe hex alpha pair (00–FF) maps to 0%–100%, so 80 in hex is roughly 0.5 (128 ÷ 255 ≈ 0.502) — close to 50% but not exactly.
Browser Support
Both formats work in every browser shipped this century. The 8-digit hex (#RRGGBBAA) is supported in all modern evergreen browsers (Chrome 62+, Firefox 49+, Safari 9.1+) — safe to use in 2026.
Frequently Asked Questions
Are HEX and RGB exactly equivalent?
Yes — both formats describe an 8-bit-per-channel sRGB colour. Any hex value has a single RGB equivalent and vice versa. #E85D04 is rgb(232, 93, 4) — identical pixels on screen.
Why does HEX use 6 digits?
Two hex digits represent one byte (0–255), and three bytes encode the red, green, and blue channels. 2 × 3 = 6 digits per colour.
What is HEXA?
An eight-digit hex code that includes an alpha channel — #RRGGBBAA. The AA pair represents opacity from 00 (fully transparent) to FF (fully opaque). Supported in modern browsers.
Which format is better for accessibility?
Neither — accessibility depends on the colour contrast ratio between text and background, which is a property of the colours themselves, not the format you use to describe them. WCAG 2.1 specifies the contrast requirements.