#283F88
Closest named color: Cobalt (#1E488F). oklch(39.3% 0.125 267.2), rgb(40, 63, 136).
Aa
White text reads best on this color (9.73:1).
About this color
#283F88 is a dark, moderately saturated blue. In OKLCH its lightness is 39%, its chroma 0.125 and its hue 267°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.026 away. White text reads best on it, at 9.73:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.15:1 |
| White text | 9.73:1 |
Values
| HEX | #283F88 |
| RGB | rgb(40, 63, 136) |
| HSL | hsl(226, 55%, 35%) |
| OKLCH | oklch(39.3% 0.125 267.2) |
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 #283F88 | 9.73:1 | AAA | Lc -96.5 | Preferred for body text |
| Black text on #283F88 | 2.15:1 | Fails | Lc 11.7 | Not readable |
| #283F88 text on white | 9.73:1 | AAA | Lc 92.2 | Preferred for body text |
| #283F88 text on black | 2.15:1 | Fails | Lc -10.2 | 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 900.
-
Step 50
50
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E2EAFD
oklch(93.7% 0.027 267.5)
-
Step 200
200
#CAD9FD
oklch(88.6% 0.052 267.4)
-
Step 300
300
#A6BFFE
oklch(80.9% 0.094 267.6)
-
Step 400
400
#779BFE
oklch(70.7% 0.151 267.4)
-
Step 500
500
#567EFC
oklch(63% 0.193 267.4)
-
Step 600
600
#3E64EB
oklch(55.7% 0.208 267.2)
-
Step 700
700
#3151CD
oklch(49.1% 0.195 267.4)
-
Step 800
800
#2844A5
oklch(42.7% 0.16 267)
-
Step 900
900 (this color)
#283F88
oklch(39.3% 0.125 267.2)
-
Step 950
950
#15234D
oklch(27% 0.08 267.1)
#283F88 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) | #10498B | 0.030 |
| Deuteranopia (no green cones) | #004087 | 0.028 |
| Tritanopia (no blue cones) | #00505D | 0.101 |
| Achromatopsia (no color) | #444444 | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #283F88
#283F88
oklch(39.3% 0.125 267.2)
- #584200
#584200
oklch(39.2% 0.08 87)
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 #283F88, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.026
- Twilight Blue #0A437A ΔE 0.036
- Dark Slate Blue #483D8B ΔE 0.046
- Blueberry #464196 ΔE 0.049
- Light Navy #155084 ΔE 0.050
- Dusk Blue #26538D ΔE 0.056
- Sapphire #2138AB ΔE 0.061
- Deep Sea Blue #015482 ΔE 0.064
Use #283F88 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.