#283A8A
Closest named color: Cobalt (#1E488F). oklch(38.4% 0.135 269.4), rgb(40, 58, 138).
Aa
White text reads best on this color (10.18:1).
About this color
#283A8A is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.135 and its hue 269°. 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 10.18:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.135) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.06:1 |
| White text | 10.18:1 |
Values
| HEX | #283A8A |
| RGB | rgb(40, 58, 138) |
| HSL | hsl(229, 55%, 35%) |
| OKLCH | oklch(38.4% 0.135 269.4) |
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 #283A8A | 10.18:1 | AAA | Lc -97.3 | Preferred for body text |
| Black text on #283A8A | 2.06:1 | Fails | Lc 10.7 | Not readable |
| #283A8A text on white | 10.18:1 | AAA | Lc 93.2 | Preferred for body text |
| #283A8A text on black | 2.06:1 | Fails | Lc -9.3 | 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
#CAD8FF
oklch(88.4% 0.056 269.7)
-
Step 300
300
#A8BEFF
oklch(80.9% 0.096 269.8)
-
Step 400
400
#7B9AFF
oklch(70.8% 0.152 269.4)
-
Step 500
500
#5B7CFF
oklch(63.1% 0.198 269.4)
-
Step 600
600
#435EF4
oklch(55.5% 0.225 269.6)
-
Step 700
700
#364CD4
oklch(49% 0.209 269.6)
-
Step 800
800
#2C40AC
oklch(42.8% 0.173 269.4)
-
Step 900
900 (this color)
#283A8A
oklch(38.4% 0.135 269.4)
-
Step 950
950
#16224F
oklch(27% 0.084 268.9)
#283A8A 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) | #00468D | 0.037 |
| Deuteranopia (no green cones) | #003D88 | 0.029 |
| Tritanopia (no blue cones) | #004E5C | 0.110 |
| Achromatopsia (no color) | #414141 | 0.135 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #283A8A
#283A8A
oklch(38.4% 0.135 269.4)
- #544100
#544100
oklch(38.5% 0.079 89.8)
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 #283A8A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.037
- Twilight Blue #0A437A ΔE 0.044
- Dark Slate Blue #483D8B ΔE 0.049
- Blueberry #464196 ΔE 0.053
- Sapphire #2138AB ΔE 0.055
- Light Navy #155084 ΔE 0.064
- Marine Blue #01386A ΔE 0.066
- Dusk Blue #26538D ΔE 0.069
Use #283A8A 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.