#37437F
Closest named color: Cobalt (#1E488F). oklch(40.4% 0.101 272.6), rgb(55, 67, 127).
Aa
White text reads best on this color (9.24:1).
About this color
#37437F is a dark, moderately saturated blue. In OKLCH its lightness is 40%, its chroma 0.101 and its hue 273°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.037 away. White text reads best on it, at 9.24:1.
| Hue family | Blues |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.27:1 |
| White text | 9.24:1 |
Values
| HEX | #37437F |
| RGB | rgb(55, 67, 127) |
| HSL | hsl(230, 40%, 36%) |
| OKLCH | oklch(40.4% 0.101 272.6) |
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 #37437F | 9.24:1 | AAA | Lc -95.5 | Preferred for body text |
| Black text on #37437F | 2.27:1 | Fails | Lc 12.8 | Not readable |
| #37437F text on white | 9.24:1 | AAA | Lc 91.1 | Preferred for body text |
| #37437F text on black | 2.27:1 | Fails | Lc -11.2 | 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
#E6E9F6
oklch(93.6% 0.018 275.6)
-
Step 200
200
#D1D8F0
oklch(88.4% 0.034 272.8)
-
Step 300
300
#B3BFE8
oklch(80.9% 0.06 272.2)
-
Step 400
400
#8C9DDC
oklch(70.7% 0.095 272.2)
-
Step 500
500
#7183D2
oklch(63% 0.121 272.8)
-
Step 600
600
#5A6CC0
oklch(55.7% 0.132 272.4)
-
Step 700
700
#4A59A5
oklch(49% 0.122 272.7)
-
Step 800
800 (this color)
#37437F
oklch(40.4% 0.101 272.6)
-
Step 900
900
#343E6B
oklch(37.8% 0.078 272.7)
-
Step 950
950
#1E243F
oklch(26.9% 0.051 273)
#37437F 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) | #284B81 | 0.026 |
| Deuteranopia (no green cones) | #1F447E | 0.028 |
| Tritanopia (no blue cones) | #11505B | 0.089 |
| Achromatopsia (no color) | #474747 | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #37437F
#37437F
oklch(40.4% 0.101 272.6)
- #594700
#594700
oklch(40.5% 0.083 92.2)
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 #37437F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.037
- Dark Slate Blue #483D8B ΔE 0.037
- Twilight Blue #0A437A ΔE 0.044
- Light Navy #155084 ΔE 0.045
- Blueberry #464196 ΔE 0.045
- Dusk Blue #26538D ΔE 0.048
- Twilight #4E518B ΔE 0.057
- Deep Sea Blue #015482 ΔE 0.058
Use #37437F 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.