HEX to OKLCH: #EF4444

Also known as: Tailwind v3 red-500

#EF4444 → oklch(0.637 0.208 25.3)

Values are shown at full precision, so converting back gives exactly #ef4444. The rounded form is what you normally paste into CSS.

Step-by-step math

Every number below is computed from the input, nothing is looked up.

1. sRGB → linear

R: 239/255 = 0.93725 → 0.863157  (((x + 0.055) / 1.055)^2.4)
G: 68/255 = 0.26667 → 0.057805  (((x + 0.055) / 1.055)^2.4)
B: 68/255 = 0.26667 → 0.057805  (((x + 0.055) / 1.055)^2.4)

2. linear sRGB → LMS

l = 0.4122·R + 0.5363·G + 0.0514·B = 0.389789
m = 0.2119·R + 0.6807·G + 0.1074·B = 0.228462
s = 0.0883·R + 0.2817·G + 0.6300·B = 0.128920

3. cube root

l′ = ∛0.389789 = 0.730482
m′ = ∛0.228462 = 0.611324
s′ = ∛0.128920 = 0.505173

4. LMS′ → Oklab

L = 0.2105·l′ + 0.7936·m′ − 0.0041·s′ = 0.63683
a = 1.9780·l′ − 2.4286·m′ + 0.4506·s′ = 0.18786
b = 0.0259·l′ + 0.7828·m′ − 0.8087·s′ = 0.08893

5. Oklab → OKLCH

C = √(a² + b²) = 0.20785
H = atan2(b, a) = 25.331°
L = 0.63683

6. OKLCH

oklch(0.63683 0.20785 25.331)
rounded: oklch(0.637 0.208 25.3)

All formats

HEX: #ef4444
RGB: rgb(239 68 68)
RGB (legacy): rgb(239, 68, 68)
HSL: hsl(0.00 84.24% 60.20%) → hsl(0 84% 60%)
HWB: hwb(0 27% 6%)
OKLCH: oklch(0.637 0.208 25.3) · oklch(63.7% 0.208 25.3)
OKLab: oklab(0.637 0.188 0.089)
Lab (D50): lab(55.79 65.62 40.80)
LCH (D50): lch(55.79 77.27 31.87)
Display P3: color(display-p3 0.8651 0.3219 0.2966)
Linear sRGB: color(srgb-linear 0.8632 0.0578 0.0578)

Gamut: sRGB and Display P3

#EF4444 is a hex color, so it sits inside sRGB and therefore inside Display P3. At this lightness and hue, sRGB reaches chroma 0.249 and Display P3 reaches 0.291; this color uses 84% of the sRGB chroma available.

CSS snippets

.element {
  color: #ef4444;
  color: rgb(239 68 68);
  color: hsl(0 84% 60%);
  color: oklch(0.637 0.208 25.3);
}

/* Tailwind CSS v4 */
@theme {
  --color-brand: oklch(0.637 0.208 25.3);
}
/* arbitrary values */
class="text-[#ef4444] bg-[oklch(0.637_0.208_25.3)]"

/* wide-gamut screens */
@media (color-gamut: p3) {
  .element { color: color(display-p3 0.8651 0.3219 0.2966); }
}

/* relative color syntax: 10% darker */
.element-dark { color: oklch(from #ef4444 calc(l - 0.1) c h); }

Nearby colors

Closest colors in the Tailwind and CSS named palettes (OKLab distance).

Lighter and darker, same hue and chroma

#FF5A56 · oklch(0.697 0.208 25.3) · ΔL +0.06
#D92C32 · oklch(0.577 0.208 25.3) · ΔL −0.06

Open in the studio

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