#663F8D
Closest named color: Rebecca Purple (#663399). oklch(45% 0.127 304.9), rgb(102, 63, 141).
Aa
White text reads best on this color (7.89:1).
About this color
#663F8D is a medium-dark, moderately saturated purple. In OKLCH its lightness is 45%, its chroma 0.127 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 0.035 away. White text reads best on it, at 7.89:1.
| Hue family | Purples |
| Lightness | medium-dark (45%) |
| Chroma | moderately saturated (0.127) |
| Temperature | in between |
| Nearest name | Rebecca Purple (#663399) |
| Black text | 2.66:1 |
| White text | 7.89:1 |
Values
| HEX | #663F8D |
| RGB | rgb(102, 63, 141) |
| HSL | hsl(270, 38%, 40%) |
| OKLCH | oklch(45% 0.127 304.9) |
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 #663F8D | 7.89:1 | AAA | Lc -91.8 | Preferred for body text |
| Black text on #663F8D | 2.66:1 | Fails | Lc 16.9 | Dividers and decoration only |
| #663F8D text on white | 7.89:1 | AAA | Lc 87.1 | Fine for body text |
| #663F8D text on black | 2.66:1 | Fails | Lc -15.0 | Dividers and decoration only |
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
#DFD3F0
oklch(88.5% 0.041 304.3)
-
Step 300
300
#CBB5E8
oklch(80.9% 0.074 304.4)
-
Step 400
400
#B28DDC
oklch(70.7% 0.119 305.1)
-
Step 500
500
#9F6ED2
oklch(63% 0.152 305.1)
-
Step 600
600
#8A54BF
oklch(55.5% 0.165 304.9)
-
Step 700
700
#7544A5
oklch(49.1% 0.153 304.7)
-
Step 800
800 (this color)
#663F8D
oklch(45% 0.127 304.9)
-
Step 900
900
#4E316B
oklch(37.6% 0.1 305.2)
-
Step 950
950
#2E1D3F
oklch(27% 0.064 305.6)
#663F8D 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) | #245090 | 0.099 |
| Deuteranopia (no green cones) | #31518B | 0.089 |
| Tritanopia (no blue cones) | #5F4D60 | 0.092 |
| Achromatopsia (no color) | #515151 | 0.128 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #663F8D
#663F8D
oklch(45% 0.127 304.9)
- #475F00
#475F00
oklch(44.9% 0.113 124.9)
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 #663F8D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rebecca Purple #663399 ΔE 0.035
- Dark Slate Blue #483D8B ΔE 0.055
- Blueberry #464196 ΔE 0.058
- Twilight #4E518B ΔE 0.059
- Dusk #4E5481 ΔE 0.072
- Light Eggplant #894585 ΔE 0.073
- Dusty Grape #545775 ΔE 0.087
- Dusky Blue #475F94 ΔE 0.092
Use #663F8D 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.