HEX to OKLCH: #581C87

Also known as: Tailwind v3 purple-900

#581C87 → oklch(0.381 0.166 305.0)

Values are shown at full precision, so converting back gives exactly #581c87. 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: 88/255 = 0.34510 → 0.097587  (((x + 0.055) / 1.055)^2.4)
G: 28/255 = 0.10980 → 0.011612  (((x + 0.055) / 1.055)^2.4)
B: 135/255 = 0.52941 → 0.242281  (((x + 0.055) / 1.055)^2.4)

2. linear sRGB → LMS

l = 0.4122·R + 0.5363·G + 0.0514·B = 0.058920
m = 0.2119·R + 0.6807·G + 0.1074·B = 0.054604
s = 0.0883·R + 0.2817·G + 0.6300·B = 0.164521

3. cube root

l′ = ∛0.058920 = 0.389124
m′ = ∛0.054604 = 0.379380
s′ = ∛0.164521 = 0.547949

4. LMS′ → Oklab

L = 0.2105·l′ + 0.7936·m′ − 0.0041·s′ = 0.38074
a = 1.9780·l′ − 2.4286·m′ + 0.4506·s′ = 0.09523
b = 0.0259·l′ + 0.7828·m′ − 0.8087·s′ = -0.13607

5. Oklab → OKLCH

C = √(a² + b²) = 0.16608
H = atan2(b, a) = 304.987°
L = 0.38074

6. OKLCH

oklch(0.38074 0.16608 304.987)
rounded: oklch(0.381 0.166 305.0)

All formats

HEX: #581c87
RGB: rgb(88 28 135)
RGB (legacy): rgb(88, 28, 135)
HSL: hsl(273.64 65.64% 31.96%) → hsl(274 66% 32%)
HWB: hwb(274 11% 47%)
OKLCH: oklch(0.381 0.166 305.0) · oklch(38.1% 0.166 305.0)
OKLab: oklab(0.381 0.095 -0.136)
Lab (D50): lab(25.18 42.12 -48.39)
LCH (D50): lch(25.18 64.15 311.03)
Display P3: color(display-p3 0.3177 0.1256 0.5097)
Linear sRGB: color(srgb-linear 0.0976 0.0116 0.2423)

Gamut: sRGB and Display P3

#581C87 is a hex color, so it sits inside sRGB and therefore inside Display P3. At this lightness and hue, sRGB reaches chroma 0.198 and Display P3 reaches 0.208; this color uses 84% of the sRGB chroma available.

CSS snippets

.element {
  color: #581c87;
  color: rgb(88 28 135);
  color: hsl(274 66% 32%);
  color: oklch(0.381 0.166 305.0);
}

/* Tailwind CSS v4 */
@theme {
  --color-brand: oklch(0.381 0.166 305.0);
}
/* arbitrary values */
class="text-[#581c87] bg-[oklch(0.381_0.166_305.0)]"

/* wide-gamut screens */
@media (color-gamut: p3) {
  .element { color: color(display-p3 0.3177 0.1256 0.5097); }
}

/* relative color syntax: 10% darker */
.element-dark { color: oklch(from #581c87 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

#69309A · oklch(0.441 0.166 305.0) · ΔL +0.06
#480074 · oklch(0.321 0.166 305.0) · ΔL −0.06

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