Red is the CSS named color #FF0000 — rgb(255, 0, 0), hsl(0, 100%, 50%). Its relative luminance is 0.213, giving 4.00:1 against white and 5.25:1 against black, so it works as a text color on black.
| HEX | #FF0000 |
|---|---|
| RGB | rgb(255, 0, 0) |
| HSL | hsl(0, 100%, 50%) |
| Relative luminance | 0.2126 |
| Contrast on white | 4.00:1 large text only |
| Contrast on black | 5.25:1 AA pass |
Built by mixing red toward white (four steps) and toward black (four steps) while keeping the hue. Use the shades generator for a different step count or to add harmony sets.
Closest by CIELAB distance (ΔE76). For perceptual matching in a design system, compare in OKLab before locking a token.
red is #FF0000, which is rgb(255, 0, 0) and hsl(0, 100%, 50%). It is one of the 148 CSS named colors defined by the CSS Color Module Level 4.
Red has a relative luminance of 0.213 on a 0–1 scale, so it is a dark color. Against white it scores 4.00:1; against black, 5.25:1.
red reaches 5.25:1 against black, which clears WCAG 2.2 AA for normal text (4.5:1) at any size.