#37478B
Closest named color: Cobalt (#1E488F). oklch(42.1% 0.114 270.9), rgb(55, 71, 139).
Aa
White text reads best on this color (8.61:1).
About this color
#37478B is a dark, moderately saturated blue. In OKLCH its lightness is 42%, its chroma 0.114 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.027 away. White text reads best on it, at 8.61:1.
| Hue family | Blues |
| Lightness | dark (42%) |
| Chroma | moderately saturated (0.114) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.43:1 |
| White text | 8.61:1 |
Values
| HEX | #37478B |
| RGB | rgb(55, 71, 139) |
| HSL | hsl(229, 43%, 38%) |
| OKLCH | oklch(42.1% 0.114 270.9) |
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 #37478B | 8.61:1 | AAA | Lc -93.9 | Preferred for body text |
| Black text on #37478B | 2.43:1 | Fails | Lc 14.6 | Not readable |
| #37478B text on white | 8.61:1 | AAA | Lc 89.4 | Fine for body text |
| #37478B text on black | 2.43:1 | Fails | Lc -12.9 | 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
#E5E9F7
oklch(93.5% 0.019 273.2)
-
Step 200
200
#D0D8F2
oklch(88.4% 0.037 272)
-
Step 300
300
#B0BFED
oklch(80.9% 0.067 270.7)
-
Step 400
400
#889DE3
oklch(70.8% 0.106 270.8)
-
Step 500
500
#6B83DB
oklch(63.1% 0.135 270.6)
-
Step 600
600
#546AC9
oklch(55.5% 0.149 271)
-
Step 700
700
#4558AE
oklch(49.1% 0.138 271.1)
-
Step 800
800 (this color)
#37478B
oklch(42.1% 0.114 270.9)
-
Step 900
900
#303D70
oklch(37.6% 0.089 270.9)
-
Step 950
950
#1C2442
oklch(26.9% 0.057 270.9)
#37478B 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) | #26508E | 0.028 |
| Deuteranopia (no green cones) | #18488A | 0.031 |
| Tritanopia (no blue cones) | #005662 | 0.100 |
| Achromatopsia (no color) | #4C4C4C | 0.114 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #37478B
#37478B
oklch(42.1% 0.114 270.9)
- #5F4B00
#5F4B00
oklch(42.2% 0.086 91.1)
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 #37478B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.027
- Blueberry #464196 ΔE 0.032
- Dark Slate Blue #483D8B ΔE 0.034
- Dusk Blue #26538D ΔE 0.036
- Light Navy #155084 ΔE 0.041
- Twilight #4E518B ΔE 0.046
- Twilight Blue #0A437A ΔE 0.054
- Deep Sea Blue #015482 ΔE 0.054
Use #37478B 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.