#373387
Closest named color: Dark Slate Blue (#483D8B). oklch(37.8% 0.136 279.8), rgb(55, 51, 135).
Aa
White text reads best on this color (10.57:1).
About this color
#373387 is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.136 and its hue 280°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.041 away. White text reads best on it, at 10.57:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.136) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 1.98:1 |
| White text | 10.57:1 |
Values
| HEX | #373387 |
| RGB | rgb(55, 51, 135) |
| HSL | hsl(243, 45%, 36%) |
| OKLCH | oklch(37.8% 0.136 279.8) |
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 #373387 | 10.57:1 | AAA | Lc -98.1 | Preferred for body text |
| Black text on #373387 | 1.98:1 | Fails | Lc 9.8 | Not readable |
| #373387 text on white | 10.57:1 | AAA | Lc 94.1 | Preferred for body text |
| #373387 text on black | 1.98:1 | Fails | Lc -8.4 | 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
#F3F5FF
oklch(97.2% 0.013 277.1)
-
Step 100
100
#E5E8FE
oklch(93.5% 0.03 279.6)
-
Step 200
200
#D1D6FF
oklch(88.5% 0.057 279.7)
-
Step 300
300
#B4BAFF
oklch(80.9% 0.098 280.1)
-
Step 400
400
#8F93FF
oklch(70.7% 0.156 280)
-
Step 500
500
#7673FF
oklch(63.1% 0.202 279.9)
-
Step 600
600
#6154F2
oklch(55.5% 0.227 279.7)
-
Step 700
700
#5143D3
oklch(49.1% 0.211 279.6)
-
Step 800
800
#4238AA
oklch(42.6% 0.175 279.9)
-
Step 900
900 (this color)
#373387
oklch(37.8% 0.136 279.8)
-
Step 950
950
#201F4F
oklch(27.1% 0.086 279.9)
#373387 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) | #00428A | 0.056 |
| Deuteranopia (no green cones) | #003B85 | 0.052 |
| Tritanopia (no blue cones) | #074758 | 0.116 |
| Achromatopsia (no color) | #3F3F3F | 0.136 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373387
#373387
oklch(37.8% 0.136 279.8)
- #4C4200
#4C4200
oklch(37.8% 0.078 99.5)
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 #373387, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.041
- Blueberry #464196 ΔE 0.051
- Cobalt #1E488F ΔE 0.058
- Twilight Blue #0A437A ΔE 0.063
- Sapphire #2138AB ΔE 0.065
- Marine Blue #01386A ΔE 0.076
- Imperial Purple #480CA8 ΔE 0.078
- Indigo Blue #3A18B1 ΔE 0.079
Use #373387 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.