Color Ruler
Enter a six-digit HEX color and adjust opacity to explore transparent preview, RGB, HSL, uncalibrated arithmetic CMYK, and palette relationships.
Color Ruler
CMYK is arithmetic and uncalibrated, not an ICC print match. Opacity changes the preview only; names and harmonies use the source color. Numeric tokens are limited to 64 characters. Nonzero inputs or hue unit conversions that underflow to zero are rejected; JavaScript floating point precision still applies.
A QUICK WALKTHROUGH
How to use this tool
- Enter a valid six-digit HEX value and set opacity from 0 to 1.
- Review the preview, RGB, HSL, and arithmetic CMYK values.
- Copy values or inspect complementary, analogous, and triadic swatches.
- Choose a purpose, then copy the report or download UTF-8 TXT; convert again after editing.
Six-digit HEX scope
Only opaque six-digit HEX input is accepted, with or without #. Three-digit shorthand, alpha HEX, RGB input, and named input are outside this tool.
Transparent preview
Opacity is finite and limited to 0 through 1. The checkerboard preview represents CSS compositing and does not alter the source color.
Color references
RGB distance is transparent Euclidean channel distance. The nearest name is limited to the existing 148-name CSS mapping; CMYK is uncalibrated arithmetic and is not an ICC print match.
All nearest ties and complete formats
The reference is the standard 148 CSS named colors, including aliases. Search uses squared Euclidean distance in the original gamma-encoded RGB channels (0–255); all equal minimum distances are listed. This is not perceptual matching, a brand palette or a commercial color standard. RGB, HSL and arithmetic CMYK (including the black K channel) are retained. Each complementary (+180°, −180°, base), analogous (+30°, −30°, base) and triadic (+120°, −120°, base) swatch includes all four formats.
Workflow and downloadable report
Choose CSS authoring, design handoff or learning as your report scenario. Copy or download an actual UTF-8 TXT with raw HEX and opacity, parsed RGB/HSL with units, color model, all values, all nearest ties and distances, and every harmony. Numeric calculations use JavaScript Number precision; HEX rounds to 8-bit. Opacity affects only the checkerboard preview, with no assumed background or composite matching. Edits and reset invalidate results; a selectable report remains available when clipboard access fails. Numeric tokens are limited to 64 characters. Nonzero inputs or hue unit conversions that underflow to zero are rejected; JavaScript floating point precision still applies.
GOOD TO KNOW
Common questions
Does CMYK match a printer?
No. It is an uncalibrated arithmetic conversion for reference, not an ICC profile conversion or print proof.
How many CSS names are searched?
The tool searches the existing fixed mapping of 148 CSS named colors, including aliases.
Can I enter an alpha HEX?
No. Enter exactly six HEX digits; use the opacity control for the transparent preview.
Why are several names returned?
CSS has aliases such as aqua/cyan and gray/grey; different colors may also share the same RGB distance. All equal closest names are kept.