#373D66
Closest named color: Dark Grey Blue (#29465B). oklch(37.5% 0.071 276.1), rgb(55, 61, 102).
Aa
White text reads best on this color (10.38:1).
About this color
#373D66 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.071 and its hue 276°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Grey Blue (#29465B), ΔE 0.042 away. White text reads best on it, at 10.38:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.071) |
| Temperature | cool |
| Nearest name | Dark Grey Blue (#29465B) |
| Black text | 2.02:1 |
| White text | 10.38:1 |
Values
| HEX | #373D66 |
| RGB | rgb(55, 61, 102) |
| HSL | hsl(232, 30%, 31%) |
| OKLCH | oklch(37.5% 0.071 276.1) |
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 #373D66 | 10.38:1 | AAA | Lc -98.1 | Preferred for body text |
| Black text on #373D66 | 2.02:1 | Fails | Lc 9.9 | Not readable |
| #373D66 text on white | 10.38:1 | AAA | Lc 94.0 | Preferred for body text |
| #373D66 text on black | 2.02:1 | 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
#F4F5FA
oklch(97.1% 0.007 277.2)
-
Step 100
100
#E7E9F4
oklch(93.6% 0.015 277.8)
-
Step 200
200
#D3D8ED
oklch(88.5% 0.029 275.1)
-
Step 300
300
#B7BEE3
oklch(80.8% 0.053 276.7)
-
Step 400
400
#929CD6
oklch(70.7% 0.086 276.4)
-
Step 500
500
#7883CA
oklch(63.1% 0.108 276.2)
-
Step 600
600
#616CB7
oklch(55.7% 0.117 275.6)
-
Step 700
700
#51599E
oklch(49.1% 0.11 276.6)
-
Step 800
800
#424980
oklch(42.6% 0.091 276.3)
-
Step 900
900 (this color)
#373D66
oklch(37.5% 0.071 276.1)
-
Step 950
950
#21243C
oklch(27% 0.045 277.5)
#373D66 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) | #2E4268 | 0.018 |
| Deuteranopia (no green cones) | #2B3E65 | 0.017 |
| Tritanopia (no blue cones) | #27454C | 0.063 |
| Achromatopsia (no color) | #404040 | 0.071 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373D66
#373D66
oklch(37.5% 0.071 276.1)
- #4C400B
#4C400B
oklch(37.4% 0.07 95.6)
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 #373D66, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Grey Blue #29465B ΔE 0.042
- Prussian Blue #1D3557 ΔE 0.052
- Twilight Blue #0A437A ΔE 0.052
- Charcoal #264653 ΔE 0.054
- Dark Blue Grey #1F3B4D ΔE 0.057
- Marine Blue #01386A ΔE 0.058
- Onyx #343A40 ΔE 0.066
- Charcoal Grey #3C4142 ΔE 0.068
Use #373D66 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.