# freecolorconvert.app

> Free online color converter supporting HEX, RGB, HSL, HSV/HSB, and CMYK formats.

## About

freecolorconvert.app is a free, client-side color conversion tool. All processing happens in the browser — no data is sent to any server.

## Features

- Bidirectional conversion between HEX, RGB, HSL, HSV/HSB, and CMYK
- CSS output in rgb(), hsl(), or hex format
- Native browser color picker
- Color harmonies: Complementary, Analogous, Triadic, Split-Complementary, Tetradic
- WCAG 2.1 contrast ratio checker with AA/AAA ratings for normal and large text
- Nearest CSS named color detection (148 colors)
- Recent color history (last 10, stored in localStorage)
- Auto-detect pasted formats: hex, rgb(), hsl(), named CSS colors
- URL hash support for sharing colors (e.g. freecolorconvert.app/#C49A2A)
- Dark mode with localStorage persistence
- Offline support via service worker
- Fully responsive mobile layout

## Supported Color Formats

- **HEX**: #C49A2A (3 or 6 digit)
- **RGB**: R 0-255, G 0-255, B 0-255
- **HSL**: H 0-360°, S 0-100%, L 0-100%
- **HSV/HSB**: H 0-360°, S 0-100%, V 0-100%
- **CMYK**: C 0-100%, M 0-100%, Y 0-100%, K 0-100%

## Conversion Formulas

HEX ↔ RGB: Direct hexadecimal to decimal conversion.
RGB → HSL: Normalize to 0-1, compute max/min, derive H from dominant channel, S from delta/sum, L from midpoint.
RGB → HSV: Same hue calculation, V = max, S = delta/max.
RGB → CMYK: K = 1 - max(R',G',B'), then C/M/Y from (1-channel-K)/(1-K).
WCAG Luminance: L = 0.2126·R' + 0.7152·G' + 0.0722·B' with gamma 2.2. Ratio = (L1+0.05)/(L2+0.05).

## URL

https://freecolorconvert.app/