#31337B
Closest named color: Twilight Blue (#0A437A). oklch(36.3% 0.12 277.4), rgb(49, 51, 123).
Aa
White text reads best on this color (11.11:1).
About this color
#31337B is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.120 and its hue 277°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.053 away. White text reads best on it, at 11.11:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.89:1 |
| White text | 11.11:1 |
Values
| HEX | #31337B |
| RGB | rgb(49, 51, 123) |
| HSL | hsl(238, 43%, 34%) |
| OKLCH | oklch(36.3% 0.12 277.4) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #31337B | 11.11:1 | AAA | Lc -99.2 | Preferred for body text |
| Black text on #31337B | 1.89:1 | Fails | Lc 8.5 | Not readable |
| #31337B text on white | 11.11:1 | AAA | Lc 95.4 | Preferred for body text |
| #31337B text on black | 1.89:1 | Fails | Lc 0.0 | Not readable |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 900.
-
Step 50
50
#F3F5FE
oklch(97.1% 0.012 276.1)
-
Step 100
100
#E5E9FC
oklch(93.7% 0.026 276.4)
-
Step 200
200
#D0D7FB
oklch(88.5% 0.05 276.6)
-
Step 300
300
#B2BCFB
oklch(81% 0.09 277.2)
-
Step 400
400
#8B96F9
oklch(70.7% 0.144 277.2)
-
Step 500
500
#7278F5
oklch(63.1% 0.183 277.7)
-
Step 600
600
#5C5DE4
oklch(55.5% 0.2 277.4)
-
Step 700
700
#4D4CC6
oklch(49.2% 0.185 277.5)
-
Step 800
800
#3E3FA0
oklch(42.6% 0.153 277.2)
-
Step 900
900 (this color)
#31337B
oklch(36.3% 0.12 277.4)
-
Step 950
950
#1E214B
oklch(27.1% 0.077 276.9)
#31337B with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #003F7D | 0.049 |
| Deuteranopia (no green cones) | #00397A | 0.045 |
| Tritanopia (no blue cones) | #024451 | 0.105 |
| Achromatopsia (no color) | #3C3C3C | 0.120 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #31337B
#31337B
oklch(36.3% 0.12 277.4)
- #493E00
#493E00
oklch(36.4% 0.075 97.9)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #31337B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.053
- Dark Slate Blue #483D8B ΔE 0.055
- Marine Blue #01386A ΔE 0.057
- Cobalt #1E488F ΔE 0.063
- Blueberry #464196 ΔE 0.068
- Prussian Blue #1D3557 ΔE 0.070
- Marine #042E60 ΔE 0.072
- Midnight Blue #191970 ΔE 0.080
Use #31337B in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.