#6366C4
Closest named color: Dark Periwinkle (#665FD1). oklch(55.4% 0.143 279.3), rgb(99, 102, 196).
Aa
White text reads best on this color (4.96:1).
About this color
#6366C4 is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.143 and its hue 279°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.028 away. White text reads best on it, at 4.96:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.143) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.22:1 |
| White text | 4.96:1 |
Values
| HEX | #6366C4 |
| RGB | rgb(99, 102, 196) |
| HSL | hsl(238, 45%, 58%) |
| OKLCH | oklch(55.4% 0.143 279.3) |
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 #6366C4 | 4.96:1 | AA | Lc -79.6 | Fine for body text |
| Black text on #6366C4 | 4.22:1 | AA large text | Lc 29.9 | Dividers and decoration only |
| #6366C4 text on white | 4.96:1 | AA | Lc 74.2 | Content text, not long reading |
| #6366C4 text on black | 4.22:1 | AA large text | Lc -27.5 | 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 600.
-
Step 50
50
#F4F5FB
oklch(97.1% 0.008 278.6)
-
Step 100
100
#E7E9F7
oklch(93.7% 0.019 279.5)
-
Step 200
200
#D4D7F1
oklch(88.5% 0.036 280.4)
-
Step 300
300
#B7BDEA
oklch(80.9% 0.064 278.9)
-
Step 400
400
#939AE0
oklch(70.8% 0.102 279)
-
Step 500
500
#7A7FD7
oklch(63.1% 0.131 279.5)
-
Step 600
600 (this color)
#6366C4
oklch(55.4% 0.143 279.3)
-
Step 700
700
#5355AA
oklch(49.2% 0.133 279.3)
-
Step 800
800
#44468A
oklch(42.8% 0.11 279.4)
-
Step 900
900
#393B6E
oklch(37.7% 0.086 279.7)
-
Step 950
950
#212340
oklch(27% 0.054 279.2)
#6366C4 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) | #3C74C7 | 0.053 |
| Deuteranopia (no green cones) | #346CC2 | 0.054 |
| Tritanopia (no blue cones) | #3E7A8B | 0.125 |
| Achromatopsia (no color) | #707070 | 0.143 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6366C4
#6366C4
oklch(55.4% 0.143 279.3)
- #847300
#847300
oklch(55.5% 0.115 98.9)
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 #6366C4, closest first.
No curated palette has a color within ΔE 0.04 of #6366C4.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.028
- Slate Blue #6A5ACD ΔE 0.034
- Iris #6258C4 ΔE 0.035
- Light Indigo #6D5ACF ΔE 0.037
- French Blue #436BAD ΔE 0.057
- Royal Blue #4169E1 ΔE 0.058
- Warm Blue #4B57DB ΔE 0.065
- Windows Blue #3778BF ΔE 0.065
Use #6366C4 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.