#28378E
Closest named color: Cobalt (#1E488F). oklch(38.1% 0.144 270.5), rgb(40, 55, 142).
Aa
White text reads best on this color (10.35:1).
About this color
#28378E is a dark, vivid blue. In OKLCH its lightness is 38%, its chroma 0.144 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.044 away. White text reads best on it, at 10.35:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | vivid (0.144) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.02:1 |
| White text | 10.35:1 |
Values
| HEX | #28378E |
| RGB | rgb(40, 55, 142) |
| HSL | hsl(231, 56%, 36%) |
| OKLCH | oklch(38.1% 0.144 270.5) |
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 #28378E | 10.35:1 | AAA | Lc -97.6 | Preferred for body text |
| Black text on #28378E | 2.02:1 | Fails | Lc 10.4 | Not readable |
| #28378E text on white | 10.35:1 | AAA | Lc 93.6 | Preferred for body text |
| #28378E text on black | 2.02:1 | Fails | Lc -8.9 | 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 900.
-
Step 50
50
#F2F5FF
oklch(97.1% 0.014 272.7)
-
Step 100
100
#E2E9FF
oklch(93.5% 0.031 271.7)
-
Step 200
200
#CBD8FF
oklch(88.5% 0.056 270.7)
-
Step 300
300
#A9BEFF
oklch(80.9% 0.095 270.4)
-
Step 400
400
#7D99FF
oklch(70.7% 0.152 270.5)
-
Step 500
500
#5E7BFF
oklch(63.1% 0.198 270.4)
-
Step 600
600
#4559FD
oklch(55.6% 0.241 270.6)
-
Step 700
700
#3847DC
oklch(49% 0.224 270.7)
-
Step 800
800
#2D3CB2
oklch(42.6% 0.186 270.4)
-
Step 900
900 (this color)
#28378E
oklch(38.1% 0.144 270.5)
-
Step 950
950
#162152
oklch(27.1% 0.09 269.8)
#28378E 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) | #004591 | 0.041 |
| Deuteranopia (no green cones) | #003C8C | 0.030 |
| Tritanopia (no blue cones) | #004D5D | 0.116 |
| Achromatopsia (no color) | #404040 | 0.145 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #28378E
#28378E
oklch(38.1% 0.144 270.5)
- #534000
#534000
oklch(38.1% 0.078 89.6)
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 #28378E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.044
- Sapphire #2138AB ΔE 0.048
- Twilight Blue #0A437A ΔE 0.053
- Dark Slate Blue #483D8B ΔE 0.053
- Blueberry #464196 ΔE 0.055
- Marine Blue #01386A ΔE 0.071
- Light Navy #155084 ΔE 0.072
- Indigo Blue #3A18B1 ΔE 0.076
Use #28378E 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.