#66378B
Closest named color: Rebecca Purple (#663399). oklch(43.6% 0.138 307.4), rgb(102, 55, 139).
Aa
White text reads best on this color (8.45:1).
About this color
#66378B is a dark, moderately saturated purple. In OKLCH its lightness is 44%, its chroma 0.138 and its hue 307°. Its hue sits between the warm and cool halves of the wheel. The nearest named color is Rebecca Purple (#663399), ΔE 0.025 away. White text reads best on it, at 8.45:1.
| Hue family | Purples |
| Lightness | dark (44%) |
| Chroma | moderately saturated (0.138) |
| Temperature | in between |
| Nearest name | Rebecca Purple (#663399) |
| Black text | 2.48:1 |
| White text | 8.45:1 |
Values
| HEX | #66378B |
| RGB | rgb(102, 55, 139) |
| HSL | hsl(274, 43%, 38%) |
| OKLCH | oklch(43.6% 0.138 307.4) |
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 #66378B | 8.45:1 | AAA | Lc -93.3 | Preferred for body text |
| Black text on #66378B | 2.48:1 | Fails | Lc 15.3 | Dividers and decoration only |
| #66378B text on white | 8.45:1 | AAA | Lc 88.7 | Fine for body text |
| #66378B text on black | 2.48:1 | Fails | Lc -13.5 | 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
#EEE6F6
oklch(93.6% 0.023 308.2)
-
Step 200
200
#E1D2F1
oklch(88.5% 0.045 307.2)
-
Step 300
300
#CFB3EA
oklch(80.9% 0.082 307.7)
-
Step 400
400
#B68ADF
oklch(70.7% 0.129 307.2)
-
Step 500
500
#A46AD5
oklch(63.1% 0.164 307.4)
-
Step 600
600
#904EC3
oklch(55.6% 0.18 307.6)
-
Step 700
700
#7A3EA8
oklch(49% 0.167 307.4)
-
Step 800
800 (this color)
#66378B
oklch(43.6% 0.138 307.4)
-
Step 900
900
#512F6D
oklch(37.8% 0.107 307.4)
-
Step 950
950
#2F1C40
oklch(27% 0.068 306.8)
#66378B 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) | #154B8E | 0.115 |
| Deuteranopia (no green cones) | #2A4D89 | 0.102 |
| Tritanopia (no blue cones) | #60475B | 0.099 |
| Achromatopsia (no color) | #4D4D4D | 0.139 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #66378B
#66378B
oklch(43.6% 0.138 307.4)
- #405C00
#405C00
oklch(43.6% 0.113 127.3)
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 #66378B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Rebecca Purple #663399 ΔE 0.025
- Dark Slate Blue #483D8B ΔE 0.055
- Blueberry #464196 ΔE 0.061
- Twilight #4E518B ΔE 0.074
- Light Eggplant #894585 ΔE 0.081
- Purple #800080 ΔE 0.083
- Dusk #4E5481 ΔE 0.086
- Grape #7209B7 ΔE 0.092
Use #66378B 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.