#663F91
Closest named color: Rebecca Purple (#663399). oklch(45.3% 0.132 303.5), rgb(102, 63, 145).
Aa
White text reads best on this color (7.82:1).
About this color
#663F91 is a medium-dark, moderately saturated purple. In OKLCH its lightness is 45%, its chroma 0.132 and its hue 303°. Its hue sits between the warm and cool halves of the wheel. The nearest named color is Rebecca Purple (#663399), ΔE 0.031 away. White text reads best on it, at 7.82:1.
| Hue family | Purples |
| Lightness | medium-dark (45%) |
| Chroma | moderately saturated (0.132) |
| Temperature | in between |
| Nearest name | Rebecca Purple (#663399) |
| Black text | 2.68:1 |
| White text | 7.82:1 |
Values
| HEX | #663F91 |
| RGB | rgb(102, 63, 145) |
| HSL | hsl(269, 39%, 41%) |
| OKLCH | oklch(45.3% 0.132 303.5) |
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 #663F91 | 7.82:1 | AAA | Lc -91.6 | Preferred for body text |
| Black text on #663F91 | 2.68:1 | Fails | Lc 17.2 | Dividers and decoration only |
| #663F91 text on white | 7.82:1 | AAA | Lc 86.8 | Fine for body text |
| #663F91 text on black | 2.68:1 | Fails | Lc -15.2 | 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
#EDE7F7
oklch(93.7% 0.022 302.9)
-
Step 200
200
#DFD3F1
oklch(88.6% 0.043 303.7)
-
Step 300
300
#CBB5EA
oklch(80.9% 0.077 303.6)
-
Step 400
400
#B18CE0
oklch(70.7% 0.125 303.6)
-
Step 500
500
#9E6ED7
oklch(63.2% 0.158 303.3)
-
Step 600
600
#8953C4
oklch(55.6% 0.172 303.3)
-
Step 700
700
#7543A9
oklch(49.2% 0.159 303.7)
-
Step 800
800 (this color)
#663F91
oklch(45.3% 0.132 303.5)
-
Step 900
900
#4D316E
oklch(37.7% 0.104 303)
-
Step 950
950
#2D1D40
oklch(26.9% 0.065 303.4)
#663F91 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) | #205194 | 0.101 |
| Deuteranopia (no green cones) | #2E528F | 0.092 |
| Tritanopia (no blue cones) | #5E4F62 | 0.098 |
| Achromatopsia (no color) | #525252 | 0.133 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #663F91
#663F91
oklch(45.3% 0.132 303.5)
- #4A5F00
#4A5F00
oklch(45.2% 0.111 123.3)
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 #663F91, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rebecca Purple #663399 ΔE 0.031
- Dark Slate Blue #483D8B ΔE 0.055
- Blueberry #464196 ΔE 0.056
- Twilight #4E518B ΔE 0.060
- Dusk #4E5481 ΔE 0.074
- Light Eggplant #894585 ΔE 0.074
- Bluey Purple #6241C7 ΔE 0.087
- Dusty Grape #545775 ΔE 0.091
Use #663F91 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.