Color Code Validator
Validate HEX, RGB, RGBA, HSL, and named colors. See live swatch and format conversions.
Why use a dedicated color code validator instead of guessing?
CSS color values look deceptively simple, but small mistakes: a missing # on a hex code, an out-of-range RGB channel, or a forgotten % on an HSL saturation value: cause the browser to silently ignore the rule and fall back to a default. That means your carefully chosen brand color simply does not render, and the bug can be almost impossible to spot visually. A dedicated validator catches these errors in milliseconds.
Beyond catching typos, AlteredIdea's color validator gives you instant format conversions between HEX, RGB, and HSL. When a designer hands you an HSL value but your codebase uses HEX, or a legacy stylesheet uses named colors that you need to convert to RGB for a JavaScript animation, the conversions are already there: no extra tool needed.
How to validate: step by step
- 1Enter a color value
Type or paste any color code into the Live Preview input: HEX (#3b82f6), RGB, RGBA, HSL, or a CSS named color like 'tomato'. - 2See instant validation
The color swatch updates in real time, showing exactly what the color looks like. An error message explains why invalid values are rejected. - 3Read the format conversions
For valid colors, the tool automatically converts the value to HEX, RGB, and HSL: all displayed side by side. - 4Switch to bulk mode
Paste a list of colors one per line into the Bulk Validation textarea to check dozens of values at once. - 5Review the results
Each line is shown with a pass/fail badge, a swatch thumbnail, and all equivalent format representations.
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Frequently Asked Questions
- What color formats does this validator support?
- The validator supports six formats: 3-digit HEX (#abc), 6-digit HEX (#aabbcc), RGB (rgb(r, g, b)), RGBA (rgba(r, g, b, a)), HSL (hsl(h, s%, l%)), and CSS named colors such as 'red', 'teal', or 'navy'.
- What makes a HEX color invalid?
- A HEX value is invalid if it is missing the leading #, uses characters outside 0-9 and a-f, or has a length other than 3 or 6 digits. For example, #gg0000 and #12345 are both invalid.
- What are the valid ranges for RGB values?
- Each R, G, and B channel must be an integer between 0 and 255 inclusive. For RGBA, the alpha channel must be a decimal between 0 (fully transparent) and 1 (fully opaque).
- Does this validator work offline?
- Yes. All validation logic runs entirely in your browser: no data is sent to any server. The tool works without an internet connection once the page has loaded.
- Can I validate multiple colors at once?
- Yes. Use the Bulk Validation section and enter one color per line. The tool will display a pass/fail result for every line, along with the swatch and converted values for each valid color.
- How does the HSL to HEX conversion work?
- The tool first converts HSL to RGB using the standard algorithm (computing chroma, then mapping hue sectors to R/G/B components), and then converts the resulting RGB values to a two-digit hexadecimal representation per channel.
- Is 'transparent' a valid color?
- Transparent is not in the set of recognized CSS named colors this tool checks. If you need to represent a fully transparent color, use rgba(0, 0, 0, 0).
- Why does my color show as invalid when it looks correct?
- Common causes include extra spaces inside parentheses that break the pattern, using commas incorrectly, or forgetting the % sign in HSL values. The error message next to each result explains the exact reason.
- What is the difference between RGB and RGBA?
- RGB defines a fully opaque color with three channels: red, green, and blue. RGBA adds a fourth alpha channel that controls opacity, where 0 is invisible and 1 is completely opaque.
- Is there a limit to how many colors I can check?
- There is no hard limit. The bulk validator processes every non-empty line you enter. For very large lists (thousands of lines), performance depends on your browser, but typical use cases run instantly.
AlteredIdea vs alternatives
vs regex testing manually: Instant validation with clear pass/fail feedback and explanation of why something is invalid.
vs library functions: No coding needed. Paste and validate instantly.
vs paid tools: Completely free, no account, unlimited checks.