#663B71
Closest named color: Dark Slate Blue (#483D8B). oklch(42.7% 0.1 319.2), rgb(102, 59, 113).
Aa
White text reads best on this color (8.64:1).
About this color
#663B71 is a dark, moderately saturated purple. In OKLCH its lightness is 43%, its chroma 0.100 and its hue 319°. Its hue sits between the warm and cool halves of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.070 away. White text reads best on it, at 8.64:1.
| Hue family | Purples |
| Lightness | dark (43%) |
| Chroma | moderately saturated (0.100) |
| Temperature | in between |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.42:1 |
| White text | 8.64:1 |
Values
| HEX | #663B71 |
| RGB | rgb(102, 59, 113) |
| HSL | hsl(288, 31%, 34%) |
| OKLCH | oklch(42.7% 0.1 319.2) |
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 #663B71 | 8.64:1 | AAA | Lc -94.0 | Preferred for body text |
| Black text on #663B71 | 2.42:1 | Fails | Lc 14.5 | Not readable |
| #663B71 text on white | 8.64:1 | AAA | Lc 89.4 | Fine for body text |
| #663B71 text on black | 2.42:1 | Fails | Lc -12.8 | 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
#F8F4F9
oklch(97.2% 0.008 319.4)
-
Step 100
100
#EFE6F1
oklch(93.5% 0.018 320.1)
-
Step 200
200
#E3D3E7
oklch(88.6% 0.032 319.5)
-
Step 300
300
#D1B5D9
oklch(80.8% 0.058 318.7)
-
Step 400
400
#BA8EC6
oklch(70.7% 0.093 318.9)
-
Step 500
500
#A871B7
oklch(63.1% 0.119 318.9)
-
Step 600
600
#9358A3
oklch(55.6% 0.129 318.8)
-
Step 700
700
#7D478B
oklch(49% 0.121 319.1)
-
Step 800
800 (this color)
#663B71
oklch(42.7% 0.1 319.2)
-
Step 900
900
#53335B
oklch(37.6% 0.077 319.4)
-
Step 950
950
#311E36
oklch(27% 0.05 319.1)
#663B71 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) | #324973 | 0.089 |
| Deuteranopia (no green cones) | #3E4D6F | 0.080 |
| Tritanopia (no blue cones) | #664250 | 0.064 |
| Achromatopsia (no color) | #4C4C4C | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #663B71
#663B71
oklch(42.7% 0.1 319.2)
- #2F5B23
#2F5B23
oklch(42.5% 0.099 139.4)
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 #663B71, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.070
- Rebecca Purple #663399 ΔE 0.071
- Twilight #4E518B ΔE 0.073
- Dusk #4E5481 ΔE 0.075
- Brownish Purple #76424E ΔE 0.075
- Light Eggplant #894585 ΔE 0.079
- Dusty Grape #545775 ΔE 0.080
- Blueberry #464196 ΔE 0.083
Use #663B71 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.