HEX Code Validator & Normalizer
Validate 3, 6, and 8-digit HEX color codes and normalize formatting.
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This HEX code validator checks whether a color code is correctly formatted as 3-digit, 6-digit, or 8-digit hexadecimal, flags any invalid characters or malformed input, and normalizes the result into a clean, standardized format. It's useful for developers reviewing user-submitted color values, QA teams checking design tokens or CSS files for consistency, and anyone unsure whether a hex string they copied is actually valid. Paste any hex code, with or without the leading #, and the tool instantly tells you whether it's valid, identifies its format (shorthand, full, or with alpha), and shows the normalized version - for example, expanding #f0c to #ff00cc. Everything runs locally in your browser, so pasted color values and design files never leave your device. Validation checks strictly follow the CSS Color Module hex syntax rules, so a code marked valid here will always be interpreted correctly by browsers and design tools. Paste your hex code below to validate and normalize it.
Features
- Validates 3-digit shorthand hex codes
- Validates 6-digit full hex codes
- Validates 8-digit hex codes with alpha channel
- Normalizes shorthand codes into full 6-digit format
- Flags invalid characters or incorrect code length
- Accepts hex input with or without a leading #
- Instant validation as you type, no submit button
- Displays a live swatch for any valid code entered
Why use this hex code validator & normalizer?
- Instant validation with no processing delay
- Fully client-side, so pasted design data stays private
- Strict adherence to CSS Color Module hex syntax rules
- Clean pass/fail feedback that's easy to interpret
- Free to use with unlimited validations
Frequently asked questions
What makes a HEX code valid?
A valid hex color code consists of a # followed by exactly 3, 4, 6, or 8 hexadecimal digits (0-9 and A-F), representing RGB or RGBA channels.
How do I normalize a shorthand hex code?
Each digit in a 3-digit shorthand is duplicated to form the full 6-digit code - for example, #abc normalizes to #aabbcc.
Is #GGHHII a valid hex code?
No, hex codes only allow the characters 0-9 and A-F; letters like G, H, and I are invalid and will be flagged by this validator.
Do I need the # symbol for a hex code to be valid?
In CSS, the # is required, but this tool accepts input without it and will normalize the result to include the # for you.
What's a 4-digit hex code?
A 4-digit hex code (#RGBA) is a shorthand format that includes an alpha/transparency digit alongside the shorthand RGB digits.
Why would a hex code fail validation?
Common causes include an incorrect number of digits, invalid characters outside 0-9 and A-F, or missing digits entirely - all of which this tool flags immediately.