#373780
Closest named color: Dark Slate Blue (#483D8B). oklch(38% 0.12 279), rgb(55, 55, 128).
Aa
White text reads best on this color (10.39:1).
About this color
#373780 is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.120 and its hue 279°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.038 away. White text reads best on it, at 10.39:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.02:1 |
| White text | 10.39:1 |
Values
| HEX | #373780 |
| RGB | rgb(55, 55, 128) |
| HSL | hsl(240, 40%, 36%) |
| OKLCH | oklch(38% 0.12 279) |
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 #373780 | 10.39:1 | AAA | Lc -97.9 | Preferred for body text |
| Black text on #373780 | 2.02:1 | Fails | Lc 10.1 | Not readable |
| #373780 text on white | 10.39:1 | AAA | Lc 93.8 | Preferred for body text |
| #373780 text on black | 2.02:1 | Fails | Lc -8.7 | 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
#F3F5FE
oklch(97.1% 0.012 276.1)
-
Step 100
100
#E6E8FC
oklch(93.5% 0.027 281.3)
-
Step 200
200
#D1D6FB
oklch(88.4% 0.051 279.2)
-
Step 300
300
#B4BBFB
oklch(80.9% 0.091 279.3)
-
Step 400
400
#8E95F8
oklch(70.6% 0.144 279)
-
Step 500
500
#7577F5
oklch(63.1% 0.184 279)
-
Step 600
600
#605CE4
oklch(55.6% 0.2 279)
-
Step 700
700
#504AC6
oklch(49% 0.187 279.1)
-
Step 800
800
#413EA0
oklch(42.7% 0.154 279)
-
Step 900
900 (this color)
#373780
oklch(38% 0.12 279)
-
Step 950
950
#1F204A
oklch(26.8% 0.076 278.9)
#373780 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) | #064383 | 0.051 |
| Deuteranopia (no green cones) | #003D7E | 0.051 |
| Tritanopia (no blue cones) | #134856 | 0.104 |
| Achromatopsia (no color) | #404040 | 0.120 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373780
#373780
oklch(38% 0.12 279)
- #4D4200
#4D4200
oklch(37.9% 0.078 98.5)
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 #373780, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.038
- Blueberry #464196 ΔE 0.051
- Twilight Blue #0A437A ΔE 0.053
- Cobalt #1E488F ΔE 0.053
- Marine Blue #01386A ΔE 0.068
- Light Navy #155084 ΔE 0.073
- Sapphire #2138AB ΔE 0.076
- Dusk Blue #26538D ΔE 0.077
Use #373780 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.