#37437D
Closest named color: Cobalt (#1E488F). oklch(40.3% 0.098 272.5), rgb(55, 67, 125).
Aa
White text reads best on this color (9.28:1).
About this color
#37437D is a dark, moderately saturated blue. In OKLCH its lightness is 40%, its chroma 0.098 and its hue 272°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.039 away. White text reads best on it, at 9.28:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.098) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.26:1 |
| White text | 9.28:1 |
Values
| HEX | #37437D |
| RGB | rgb(55, 67, 125) |
| HSL | hsl(230, 39%, 35%) |
| OKLCH | oklch(40.3% 0.098 272.5) |
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 #37437D | 9.28:1 | AAA | Lc -95.6 | Preferred for body text |
| Black text on #37437D | 2.26:1 | Fails | Lc 12.7 | Not readable |
| #37437D text on white | 9.28:1 | AAA | Lc 91.3 | Preferred for body text |
| #37437D text on black | 2.26:1 | Fails | Lc -11.1 | 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
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E6E9F5
oklch(93.5% 0.016 274.8)
-
Step 200
200
#D2D8EF
oklch(88.5% 0.032 274.1)
-
Step 300
300
#B4BFE7
oklch(81% 0.058 273)
-
Step 400
400
#8D9DDA
oklch(70.7% 0.091 272.6)
-
Step 500
500
#7184D0
oklch(63.1% 0.117 272)
-
Step 600
600
#5B6CBD
oklch(55.6% 0.127 272.7)
-
Step 700
700
#4A5AA3
oklch(49.1% 0.118 272.1)
-
Step 800
800 (this color)
#37437D
oklch(40.3% 0.098 272.5)
-
Step 900
900
#343E6A
oklch(37.7% 0.076 272.6)
-
Step 950
950
#1E253E
oklch(27.1% 0.048 271.1)
#37437D 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) | #2A4A7F | 0.023 |
| Deuteranopia (no green cones) | #21447C | 0.026 |
| Tritanopia (no blue cones) | #14505A | 0.087 |
| Achromatopsia (no color) | #474747 | 0.098 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #37437D
#37437D
oklch(40.3% 0.098 272.5)
- #584700
#584700
oklch(40.4% 0.083 93.2)
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 #37437D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.039
- Dark Slate Blue #483D8B ΔE 0.039
- Twilight Blue #0A437A ΔE 0.043
- Light Navy #155084 ΔE 0.045
- Blueberry #464196 ΔE 0.048
- Dusk Blue #26538D ΔE 0.049
- Deep Sea Blue #015482 ΔE 0.058
- Twilight #4E518B ΔE 0.058
Use #37437D 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.