#373B78
Closest named color: Dark Slate Blue (#483D8B). oklch(38.2% 0.102 277.6), rgb(55, 59, 120).
Aa
White text reads best on this color (10.19:1).
About this color
#373B78 is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.102 and its hue 278°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.043 away. White text reads best on it, at 10.19:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.102) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.05:1 |
| White text | 10.19:1 |
Values
| HEX | #373B78 |
| RGB | rgb(55, 59, 120) |
| HSL | hsl(236, 37%, 34%) |
| OKLCH | oklch(38.2% 0.102 277.6) |
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 #373B78 | 10.19:1 | AAA | Lc -97.6 | Preferred for body text |
| Black text on #373B78 | 2.05:1 | Fails | Lc 10.4 | Not readable |
| #373B78 text on white | 10.19:1 | AAA | Lc 93.5 | Preferred for body text |
| #373B78 text on black | 2.05:1 | Fails | Lc -9.0 | 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
#F3F5FD
oklch(97.1% 0.011 274.9)
-
Step 100
100
#E6E9F9
oklch(93.6% 0.022 277.5)
-
Step 200
200
#D2D7F6
oklch(88.5% 0.043 278.2)
-
Step 300
300
#B4BDF2
oklch(81% 0.076 277.1)
-
Step 400
400
#8E98EC
oklch(70.6% 0.123 277.6)
-
Step 500
500
#747CE6
oklch(63% 0.157 277.6)
-
Step 600
600
#5F63D4
oklch(55.6% 0.17 277.8)
-
Step 700
700
#4E51B8
oklch(49% 0.159 277.5)
-
Step 800
800
#404395
oklch(42.7% 0.132 277.7)
-
Step 900
900 (this color)
#373B78
oklch(38.2% 0.102 277.6)
-
Step 950
950
#1F2245
oklch(26.9% 0.064 277.4)
#373B78 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) | #1F447A | 0.035 |
| Deuteranopia (no green cones) | #183F77 | 0.037 |
| Tritanopia (no blue cones) | #1B4853 | 0.090 |
| Achromatopsia (no color) | #414141 | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373B78
#373B78
oklch(38.2% 0.102 277.6)
- #4F4300
#4F4300
oklch(38.4% 0.079 97.6)
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 #373B78, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.043
- Twilight Blue #0A437A ΔE 0.046
- Cobalt #1E488F ΔE 0.053
- Blueberry #464196 ΔE 0.057
- Marine Blue #01386A ΔE 0.062
- Light Navy #155084 ΔE 0.064
- Dark Grey Blue #29465B ΔE 0.069
- Prussian Blue #1D3557 ΔE 0.071
Use #373B78 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.