#373F89
Closest named color: Dark Slate Blue (#483D8B). oklch(40.3% 0.122 274.9), rgb(55, 63, 137).
Aa
White text reads best on this color (9.39:1).
About this color
#373F89 is a dark, moderately saturated blue. In OKLCH its lightness is 40%, its chroma 0.122 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.027 away. White text reads best on it, at 9.39:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.122) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.23:1 |
| White text | 9.39:1 |
Values
| HEX | #373F89 |
| RGB | rgb(55, 63, 137) |
| HSL | hsl(234, 43%, 38%) |
| OKLCH | oklch(40.3% 0.122 274.9) |
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 #373F89 | 9.39:1 | AAA | Lc -95.8 | Preferred for body text |
| Black text on #373F89 | 2.23:1 | Fails | Lc 12.5 | Not readable |
| #373F89 text on white | 9.39:1 | AAA | Lc 91.5 | Preferred for body text |
| #373F89 text on black | 2.23:1 | Fails | Lc -10.9 | 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 800.
-
Step 50
50
#F3F5FC
oklch(97.1% 0.01 273.4)
-
Step 100
100
#E5E9F8
oklch(93.5% 0.021 274)
-
Step 200
200
#D1D8F4
oklch(88.6% 0.039 274.4)
-
Step 300
300
#B3BEEF
oklch(81% 0.07 274.9)
-
Step 400
400
#8C9AE8
oklch(70.7% 0.115 275.3)
-
Step 500
500
#717FE0
oklch(63% 0.146 275.2)
-
Step 600
600
#5A67CE
oklch(55.6% 0.158 274.7)
-
Step 700
700
#4A55B3
oklch(49.2% 0.148 274.6)
-
Step 800
800 (this color)
#373F89
oklch(40.3% 0.122 274.9)
-
Step 900
900
#343B73
oklch(37.6% 0.095 275.5)
-
Step 950
950
#1E2344
oklch(27% 0.061 275)
#373F89 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) | #144A8C | 0.041 |
| Deuteranopia (no green cones) | #004387 | 0.046 |
| Tritanopia (no blue cones) | #00505D | 0.108 |
| Achromatopsia (no color) | #464646 | 0.122 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #373F89
#373F89
oklch(40.3% 0.122 274.9)
- #574700
#574700
oklch(40.3% 0.083 94.2)
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 #373F89, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.027
- Blueberry #464196 ΔE 0.032
- Cobalt #1E488F ΔE 0.034
- Twilight Blue #0A437A ΔE 0.051
- Dusk Blue #26538D ΔE 0.056
- Light Navy #155084 ΔE 0.056
- Twilight #4E518B ΔE 0.064
- Sapphire #2138AB ΔE 0.065
Use #373F89 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.