HEX to OKLCH: #82181A

Also known as: Tailwind red-900

#82181A → oklch(0.397 0.141 25.7)

Values are shown at full precision, so converting back gives exactly #82181a. 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: 130/255 = 0.50980 → 0.223228  (((x + 0.055) / 1.055)^2.4)
G: 24/255 = 0.09412 → 0.009134  (((x + 0.055) / 1.055)^2.4)
B: 26/255 = 0.10196 → 0.010330  (((x + 0.055) / 1.055)^2.4)

2. linear sRGB → LMS

l = 0.4122·R + 0.5363·G + 0.0514·B = 0.097450
m = 0.2119·R + 0.6807·G + 0.1074·B = 0.054630
s = 0.0883·R + 0.2817·G + 0.6300·B = 0.028792

3. cube root

l′ = ∛0.097450 = 0.460179
m′ = ∛0.054630 = 0.379440
s′ = ∛0.028792 = 0.306497

4. LMS′ → Oklab

L = 0.2105·l′ + 0.7936·m′ − 0.0041·s′ = 0.39673
a = 1.9780·l′ − 2.4286·m′ + 0.4506·s′ = 0.12683
b = 0.0259·l′ + 0.7828·m′ − 0.8087·s′ = 0.06108

5. Oklab → OKLCH

C = √(a² + b²) = 0.14077
H = atan2(b, a) = 25.714°
L = 0.39673

6. OKLCH

oklch(0.39673 0.14077 25.714)
rounded: oklch(0.397 0.141 25.7)

All formats

HEX: #82181a
RGB: rgb(130 24 26)
RGB (legacy): rgb(130, 24, 26)
HSL: hsl(358.87 68.83% 30.20%) → hsl(359 69% 30%)
HWB: hwb(359 9% 49%)
OKLCH: oklch(0.397 0.141 25.7) · oklch(39.7% 0.141 25.7)
OKLab: oklab(0.397 0.127 0.061)
Lab (D50): lab(28.60 44.48 28.95)
LCH (D50): lch(28.60 53.07 33.06)
Display P3: color(display-p3 0.4675 0.1345 0.1225)
Linear sRGB: color(srgb-linear 0.2232 0.0091 0.0103)

Gamut: sRGB and Display P3

#82181A is a hex color, so it sits inside sRGB and therefore inside Display P3. At this lightness and hue, sRGB reaches chroma 0.161 and Display P3 reaches 0.182; this color uses 87% of the sRGB chroma available.

CSS snippets

.element {
  color: #82181a;
  color: rgb(130 24 26);
  color: hsl(359 69% 30%);
  color: oklch(0.397 0.141 25.7);
}

/* Tailwind CSS v4 */
@theme {
  --color-brand: oklch(0.397 0.141 25.7);
}
/* arbitrary values */
class="text-[#82181a] bg-[oklch(0.397_0.141_25.7)]"

/* wide-gamut screens */
@media (color-gamut: p3) {
  .element { color: color(display-p3 0.4675 0.1345 0.1225); }
}

/* relative color syntax: 10% darker */
.element-dark { color: oklch(from #82181a 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

#962D2B · oklch(0.457 0.141 25.7) · ΔL +0.06
#6E0008 · oklch(0.337 0.141 25.7) · ΔL −0.06

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