#373C63
Closest named color: Dark Grey Blue (#29465B). oklch(37% 0.067 277), rgb(55, 60, 99).
Aa
White text reads best on this color (10.55:1).
About this color
#373C63 is a dark, muted blue. In OKLCH its lightness is 37%, its chroma 0.067 and its hue 277°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Grey Blue (#29465B), ΔE 0.041 away. White text reads best on it, at 10.55:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | muted (0.067) |
| Temperature | cool |
| Nearest name | Dark Grey Blue (#29465B) |
| Black text | 1.98:1 |
| White text | 10.55:1 |
Values
| HEX | #373C63 |
| RGB | rgb(55, 60, 99) |
| HSL | hsl(233, 29%, 30%) |
| OKLCH | oklch(37% 0.067 277) |
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 #373C63 | 10.55:1 | AAA | Lc -98.4 | Preferred for body text |
| Black text on #373C63 | 1.98:1 | Fails | Lc 9.5 | Not readable |
| #373C63 text on white | 10.55:1 | AAA | Lc 94.4 | Preferred for body text |
| #373C63 text on black | 1.98:1 | Fails | Lc -8.1 | 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
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E7E9F4
oklch(93.6% 0.015 277.8)
-
Step 200
200
#D4D8EC
oklch(88.5% 0.028 276.8)
-
Step 300
300
#B8BEE2
oklch(80.9% 0.051 277.7)
-
Step 400
400
#939CD3
oklch(70.6% 0.081 276.9)
-
Step 500
500
#7A83C7
oklch(63.1% 0.103 277.3)
-
Step 600
600
#636CB4
oklch(55.6% 0.112 276.7)
-
Step 700
700
#525A9B
oklch(49.2% 0.104 276.6)
-
Step 800
800
#434A7E
oklch(42.8% 0.086 276.3)
-
Step 900
900 (this color)
#373C63
oklch(37% 0.067 277)
-
Step 950
950
#21243B
oklch(26.9% 0.043 277.4)
#373C63 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) | #2E4165 | 0.018 |
| Deuteranopia (no green cones) | #2B3D62 | 0.017 |
| Tritanopia (no blue cones) | #29444A | 0.060 |
| Achromatopsia (no color) | #3F3F3F | 0.067 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373C63
#373C63
oklch(37% 0.067 277)
- #4A400E
#4A400E
oklch(37.1% 0.068 97.5)
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 #373C63, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Grey Blue #29465B ΔE 0.041
- Prussian Blue #1D3557 ΔE 0.049
- Charcoal #264653 ΔE 0.052
- Dark Blue Grey #1F3B4D ΔE 0.053
- Twilight Blue #0A437A ΔE 0.056
- Marine Blue #01386A ΔE 0.058
- Onyx #343A40 ΔE 0.061
- Charcoal Grey #3C4142 ΔE 0.065
Use #373C63 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.