#283D8B
Closest named color: Cobalt (#1E488F). oklch(39.1% 0.132 268.3), rgb(40, 61, 139).
Aa
White text reads best on this color (9.85:1).
About this color
#283D8B is a dark, moderately saturated blue. In OKLCH its lightness is 39%, its chroma 0.132 and its hue 268°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.030 away. White text reads best on it, at 9.85:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | moderately saturated (0.132) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.13:1 |
| White text | 9.85:1 |
Values
| HEX | #283D8B |
| RGB | rgb(40, 61, 139) |
| HSL | hsl(227, 55%, 35%) |
| OKLCH | oklch(39.1% 0.132 268.3) |
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 #283D8B | 9.85:1 | AAA | Lc -96.7 | Preferred for body text |
| Black text on #283D8B | 2.13:1 | Fails | Lc 11.5 | Not readable |
| #283D8B text on white | 9.85:1 | AAA | Lc 92.5 | Preferred for body text |
| #283D8B text on black | 2.13:1 | Fails | Lc -10.0 | 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
#E2EAFE
oklch(93.7% 0.028 268.4)
-
Step 200
200
#CAD9FF
oklch(88.6% 0.055 268.3)
-
Step 300
300
#A6BFFF
oklch(80.9% 0.095 267.8)
-
Step 400
400
#799AFF
oklch(70.6% 0.153 268.6)
-
Step 500
500
#587DFF
oklch(63.1% 0.197 268.3)
-
Step 600
600
#3F60F2
oklch(55.6% 0.221 268.3)
-
Step 700
700
#324ED2
oklch(49% 0.205 268.3)
-
Step 800
800
#2941AA
oklch(42.6% 0.17 268.2)
-
Step 900
900 (this color)
#283D8B
oklch(39.1% 0.132 268.3)
-
Step 950
950
#15224F
oklch(27% 0.084 268.2)
#283D8B 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) | #00488E | 0.035 |
| Deuteranopia (no green cones) | #003F89 | 0.028 |
| Tritanopia (no blue cones) | #00505E | 0.107 |
| Achromatopsia (no color) | #434343 | 0.132 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #283D8B
#283D8B
oklch(39.1% 0.132 268.3)
- #574200
#574200
oklch(39.1% 0.08 88)
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 #283D8B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.030
- Twilight Blue #0A437A ΔE 0.041
- Dark Slate Blue #483D8B ΔE 0.047
- Blueberry #464196 ΔE 0.049
- Sapphire #2138AB ΔE 0.054
- Light Navy #155084 ΔE 0.056
- Dusk Blue #26538D ΔE 0.061
- Marine Blue #01386A ΔE 0.068
Use #283D8B 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.