#31397B
Closest named color: Twilight Blue (#0A437A). oklch(37.6% 0.111 274.5), rgb(49, 57, 123).
Aa
White text reads best on this color (10.49:1).
About this color
#31397B is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.111 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.042 away. White text reads best on it, at 10.49:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.111) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 2.00:1 |
| White text | 10.49:1 |
Values
| HEX | #31397B |
| RGB | rgb(49, 57, 123) |
| HSL | hsl(234, 43%, 34%) |
| OKLCH | oklch(37.6% 0.111 274.5) |
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 #31397B | 10.49:1 | AAA | Lc -98.1 | Preferred for body text |
| Black text on #31397B | 2.00:1 | Fails | Lc 9.8 | Not readable |
| #31397B text on white | 10.49:1 | AAA | Lc 94.1 | Preferred for body text |
| #31397B text on black | 2.00:1 | Fails | Lc -8.5 | 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
#F3F5FD
oklch(97.1% 0.011 274.9)
-
Step 100
100
#E5E9FB
oklch(93.6% 0.025 275.9)
-
Step 200
200
#CFD8F9
oklch(88.6% 0.047 273.4)
-
Step 300
300
#B0BDF7
oklch(80.9% 0.083 274.6)
-
Step 400
400
#8899F3
oklch(70.7% 0.133 274.4)
-
Step 500
500
#6D7CEF
oklch(63.1% 0.171 274.8)
-
Step 600
600
#5762DD
oklch(55.5% 0.185 274.8)
-
Step 700
700
#4751C0
oklch(49.2% 0.172 274.3)
-
Step 800
800
#3A439B
oklch(42.7% 0.142 274.3)
-
Step 900
900 (this color)
#31397B
oklch(37.6% 0.111 274.5)
-
Step 950
950
#1D2248
oklch(27% 0.07 275)
#31397B 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) | #14437D | 0.037 |
| Deuteranopia (no green cones) | #043C7A | 0.040 |
| Tritanopia (no blue cones) | #004854 | 0.098 |
| Achromatopsia (no color) | #3F3F3F | 0.112 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #31397B
#31397B
oklch(37.6% 0.111 274.5)
- #4E4000
#4E4000
oklch(37.5% 0.077 94.9)
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 #31397B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.042
- Dark Slate Blue #483D8B ΔE 0.047
- Cobalt #1E488F ΔE 0.051
- Marine Blue #01386A ΔE 0.055
- Blueberry #464196 ΔE 0.060
- Light Navy #155084 ΔE 0.066
- Prussian Blue #1D3557 ΔE 0.070
- Dark Grey Blue #29465B ΔE 0.075
Use #31397B 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.