#663F8C
Closest named color: Rebecca Purple (#663399). oklch(45% 0.126 305.3), rgb(102, 63, 140).
Aa
White text reads best on this color (7.91:1).
About this color
#663F8C is a dark, moderately saturated purple. In OKLCH its lightness is 45%, its chroma 0.126 and its hue 305°. Its hue sits between the warm and cool halves of the wheel. The nearest named color is Rebecca Purple (#663399), ΔE 0.036 away. White text reads best on it, at 7.91:1.
| Hue family | Purples |
| Lightness | dark (45%) |
| Chroma | moderately saturated (0.126) |
| Temperature | in between |
| Nearest name | Rebecca Purple (#663399) |
| Black text | 2.65:1 |
| White text | 7.91:1 |
Values
| HEX | #663F8C |
| RGB | rgb(102, 63, 140) |
| HSL | hsl(270, 38%, 40%) |
| OKLCH | oklch(45% 0.126 305.3) |
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 #663F8C | 7.91:1 | AAA | Lc -91.9 | Preferred for body text |
| Black text on #663F8C | 2.65:1 | Fails | Lc 16.8 | Dividers and decoration only |
| #663F8C text on white | 7.91:1 | AAA | Lc 87.2 | Fine for body text |
| #663F8C text on black | 2.65:1 | Fails | Lc -15.0 | 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 800.
-
Step 50
50
#F7F4FB
oklch(97.1% 0.01 305.4)
-
Step 100
100
#EDE7F6
oklch(93.7% 0.021 304)
-
Step 200
200
#DFD3EF
oklch(88.5% 0.04 304.9)
-
Step 300
300
#CCB5E7
oklch(80.9% 0.073 305.7)
-
Step 400
400
#B28DDB
oklch(70.7% 0.117 305.4)
-
Step 500
500
#9F6FD1
oklch(63.1% 0.149 305.1)
-
Step 600
600
#8A54BE
oklch(55.5% 0.164 305.2)
-
Step 700
700
#7644A4
oklch(49.1% 0.152 305.5)
-
Step 800
800 (this color)
#663F8C
oklch(45% 0.126 305.3)
-
Step 900
900
#4E326B
oklch(37.8% 0.098 304.8)
-
Step 950
950
#2E1E3E
oklch(27.1% 0.061 305.8)
#663F8C 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) | #25508F | 0.098 |
| Deuteranopia (no green cones) | #32518A | 0.088 |
| Tritanopia (no blue cones) | #604D5F | 0.092 |
| Achromatopsia (no color) | #515151 | 0.127 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #663F8C
#663F8C
oklch(45% 0.126 305.3)
- #465F00
#465F00
oklch(44.9% 0.113 125.4)
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 #663F8C, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rebecca Purple #663399 ΔE 0.036
- Dark Slate Blue #483D8B ΔE 0.055
- Blueberry #464196 ΔE 0.058
- Twilight #4E518B ΔE 0.059
- Dusk #4E5481 ΔE 0.071
- Light Eggplant #894585 ΔE 0.072
- Dusty Grape #545775 ΔE 0.086
- Dusky Blue #475F94 ΔE 0.092
Use #663F8C 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.