HEX to OKLCH: #312E81

Also known as: Tailwind v3 indigo-900

#312E81 → oklch(0.359 0.135 278.7)

Values are shown at full precision, so converting back gives exactly #312e81. 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: 49/255 = 0.19216 → 0.030713  (((x + 0.055) / 1.055)^2.4)
G: 46/255 = 0.18039 → 0.027321  (((x + 0.055) / 1.055)^2.4)
B: 129/255 = 0.50588 → 0.219526  (((x + 0.055) / 1.055)^2.4)

2. linear sRGB → LMS

l = 0.4122·R + 0.5363·G + 0.0514·B = 0.038608
m = 0.2119·R + 0.6807·G + 0.1074·B = 0.048682
s = 0.0883·R + 0.2817·G + 0.6300·B = 0.148706

3. cube root

l′ = ∛0.038608 = 0.337980
m′ = ∛0.048682 = 0.365137
s′ = ∛0.148706 = 0.529797

4. LMS′ → Oklab

L = 0.2105·l′ + 0.7936·m′ − 0.0041·s′ = 0.35875
a = 1.9780·l′ − 2.4286·m′ + 0.4506·s′ = 0.02048
b = 0.0259·l′ + 0.7828·m′ − 0.8087·s′ = -0.13386

5. Oklab → OKLCH

C = √(a² + b²) = 0.13542
H = atan2(b, a) = 278.697°
L = 0.35875

6. OKLCH

oklch(0.35875 0.13542 278.697)
rounded: oklch(0.359 0.135 278.7)

All formats

HEX: #312e81
RGB: rgb(49 46 129)
RGB (legacy): rgb(49, 46, 129)
HSL: hsl(242.17 47.43% 34.31%) → hsl(242 47% 34%)
HWB: hwb(242 18% 49%)
OKLCH: oklch(0.359 0.135 278.7) · oklch(35.9% 0.135 278.7)
OKLab: oklab(0.359 0.020 -0.134)
Lab (D50): lab(23.58 22.24 -47.48)
LCH (D50): lch(23.58 52.43 295.09)
Display P3: color(display-p3 0.1901 0.1808 0.4872)
Linear sRGB: color(srgb-linear 0.0307 0.0273 0.2195)

Gamut: sRGB and Display P3

#312E81 is a hex color, so it sits inside sRGB and therefore inside Display P3. At this lightness and hue, sRGB reaches chroma 0.219 and Display P3 reaches 0.222; this color uses 62% of the sRGB chroma available.

CSS snippets

.element {
  color: #312e81;
  color: rgb(49 46 129);
  color: hsl(242 47% 34%);
  color: oklch(0.359 0.135 278.7);
}

/* Tailwind CSS v4 */
@theme {
  --color-brand: oklch(0.359 0.135 278.7);
}
/* arbitrary values */
class="text-[#312e81] bg-[oklch(0.359_0.135_278.7)]"

/* wide-gamut screens */
@media (color-gamut: p3) {
  .element { color: color(display-p3 0.1901 0.1808 0.4872); }
}

/* relative color syntax: 10% darker */
.element-dark { color: oklch(from #312e81 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

#3F4094 · oklch(0.419 0.135 278.7) · ΔL +0.06
#241C6E · oklch(0.299 0.135 278.7) · ΔL −0.06

Open in the studio

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