#663F9B
Closest named color: Rebecca Purple (#663399). oklch(46% 0.145 300.3), rgb(102, 63, 155).
Aa
White text reads best on this color (7.63:1).
About this color
#663F9B is a medium-dark, vivid purple. In OKLCH its lightness is 46%, its chroma 0.145 and its hue 300°. Its hue sits between the warm and cool halves of the wheel. The nearest named color is Rebecca Purple (#663399), ΔE 0.026 away. White text reads best on it, at 7.63:1.
| Hue family | Purples |
| Lightness | medium-dark (46%) |
| Chroma | vivid (0.145) |
| Temperature | in between |
| Nearest name | Rebecca Purple (#663399) |
| Black text | 2.74:1 |
| White text | 7.63:1 |
Values
| HEX | #663F9B |
| RGB | rgb(102, 63, 155) |
| HSL | hsl(265, 42%, 43%) |
| OKLCH | oklch(46% 0.145 300.3) |
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 #663F9B | 7.63:1 | AAA | Lc -91.0 | Preferred for body text |
| Black text on #663F9B | 2.74:1 | Fails | Lc 17.8 | Dividers and decoration only |
| #663F9B text on white | 7.63:1 | AAA | Lc 86.2 | Fine for body text |
| #663F9B text on black | 2.74:1 | Fails | Lc -15.9 | 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 700.
-
Step 50
50
#F6F4FB
oklch(97.1% 0.009 299.2)
-
Step 100
100
#ECE7F6
oklch(93.6% 0.021 301.1)
-
Step 200
200
#DDD4F0
oklch(88.6% 0.039 300.2)
-
Step 300
300
#C7B7E8
oklch(80.9% 0.07 299.8)
-
Step 400
400
#AC90DC
oklch(70.7% 0.112 300.5)
-
Step 500
500
#9873D2
oklch(63.2% 0.142 300.3)
-
Step 600
600
#8359BF
oklch(55.6% 0.155 300.4)
-
Step 700
700 (this color)
#663F9B
oklch(46% 0.145 300.3)
-
Step 800
800
#5A3C86
oklch(42.7% 0.12 300.1)
-
Step 900
900
#4A346B
oklch(37.7% 0.093 300.5)
-
Step 950
950
#2B1F3F
oklch(27% 0.059 299.7)
#663F9B 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) | #11539E | 0.109 |
| Deuteranopia (no green cones) | #235399 | 0.100 |
| Tritanopia (no blue cones) | #5B5267 | 0.110 |
| Achromatopsia (no color) | #535353 | 0.146 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #663F9B
#663F9B
oklch(46% 0.145 300.3)
- #506000
#506000
oklch(45.9% 0.109 120.3)
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 #663F9B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rebecca Purple #663399 ΔE 0.026
- Blueberry #464196 ΔE 0.056
- Dark Slate Blue #483D8B ΔE 0.060
- Twilight #4E518B ΔE 0.066
- Bluey Purple #6241C7 ΔE 0.071
- Blue With A Hint Of Purple #533CC6 ΔE 0.078
- Light Eggplant #894585 ΔE 0.081
- Dusk #4E5481 ΔE 0.083
Use #663F9B 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.