#373C78
Closest named color: Dark Slate Blue (#483D8B). oklch(38.4% 0.101 277), rgb(55, 60, 120).
Aa
White text reads best on this color (10.09:1).
About this color
#373C78 is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.101 and its hue 277°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.042 away. White text reads best on it, at 10.09:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.08:1 |
| White text | 10.09:1 |
Values
| HEX | #373C78 |
| RGB | rgb(55, 60, 120) |
| HSL | hsl(235, 37%, 34%) |
| OKLCH | oklch(38.4% 0.101 277) |
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 #373C78 | 10.09:1 | AAA | Lc -97.4 | Preferred for body text |
| Black text on #373C78 | 2.08:1 | Fails | Lc 10.7 | Not readable |
| #373C78 text on white | 10.09:1 | AAA | Lc 93.3 | Preferred for body text |
| #373C78 text on black | 2.08:1 | Fails | Lc -9.2 | 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
#F3F5FC
oklch(97.1% 0.01 273.4)
-
Step 100
100
#E6E9F9
oklch(93.6% 0.022 277.5)
-
Step 200
200
#D2D7F5
oklch(88.5% 0.042 278)
-
Step 300
300
#B4BDF2
oklch(81% 0.076 277.1)
-
Step 400
400
#8E99EB
oklch(70.8% 0.12 277)
-
Step 500
500
#737DE5
oklch(63% 0.155 276.8)
-
Step 600
600
#5D64D3
oklch(55.6% 0.168 276.7)
-
Step 700
700
#4D52B7
oklch(49.1% 0.157 276.8)
-
Step 800
800
#3F4494
oklch(42.7% 0.129 276.7)
-
Step 900
900 (this color)
#373C78
oklch(38.4% 0.101 277)
-
Step 950
950
#1F2245
oklch(26.9% 0.064 277.4)
#373C78 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) | #21447A | 0.032 |
| Deuteranopia (no green cones) | #1A3F77 | 0.035 |
| Tritanopia (no blue cones) | #1B4954 | 0.088 |
| Achromatopsia (no color) | #424242 | 0.101 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373C78
#373C78
oklch(38.4% 0.101 277)
- #504300
#504300
oklch(38.5% 0.079 96.5)
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 #373C78, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.042
- Twilight Blue #0A437A ΔE 0.045
- Cobalt #1E488F ΔE 0.051
- Blueberry #464196 ΔE 0.057
- Light Navy #155084 ΔE 0.062
- Marine Blue #01386A ΔE 0.062
- Dark Grey Blue #29465B ΔE 0.067
- Dusk Blue #26538D ΔE 0.069
Use #373C78 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.