About

Last updated: 2026-06-25

What is Color Tools

Color Tools is a free suite that helps designers, developers, and product managers handle common color tasks quickly and accurately. Finding harmonious color schemes, generating CSS gradient code, checking text-readability contrast, and reviewing for colorblind users can all be done in one place.

Operating principles (E-E-A-T)

• Experience — The tool order mirrors a real web/UI workflow: palette → gradient → contrast → colorblind review.
• Expertise — Contrast uses the WCAG 2.1 relative-luminance and contrast-ratio formulas, color schemes use the HSL color wheel, and the colorblind simulation uses LMS transform matrices.
• Authoritativeness — We base our criteria on published standards and official documents like the W3C WCAG, and provide source links.
• Trustworthiness — We do not hide the formulas, and we clearly note items that are approximations (such as the colorblind simulation). Input values are not collected or stored.

Standards & data basis

The criteria each tool uses are based on the following public standards and references. When a standard is revised, we update to the latest content.

• WCAG 2.1 (W3C) — contrast ratio thresholds, relative-luminance calculation
• WCAG Quick Reference — AA/AAA application criteria
• W3C WAI — general web accessibility principles

A note on accuracy

The contrast-ratio calculation follows the WCAG formula exactly, so it produces the same values as standard tools. However, the colorblind (color vision deficiency) simulation is an approximation using LMS transform matrices and may differ from an individual's actual color perception. The palette's harmony colors are also approximations based on the HSL color wheel and may need fine-tuning in real use. Confirm important decisions with real user testing and the official standards.

Contact

Send feedback or bug reports to jin@zerolabskorea.com. For how we handle personal data, see the Privacy Policy.

Last updated: 2026-06-25