#6366E3
Closest named color: Dark Periwinkle (#665FD1). oklch(57.5% 0.186 277.8), rgb(99, 102, 227).
Aa
White text reads best on this color (4.62:1).
About this color
#6366E3 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.186 and its hue 278°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.031 away. White text reads best on it, at 4.62:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.186) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.54:1 |
| White text | 4.62:1 |
Values
| HEX | #6366E3 |
| RGB | rgb(99, 102, 227) |
| HSL | hsl(239, 70%, 64%) |
| OKLCH | oklch(57.5% 0.186 277.8) |
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 #6366E3 | 4.62:1 | AA | Lc -77.2 | Fine for body text |
| Black text on #6366E3 | 4.54:1 | AA | Lc 32.3 | Non-text elements, placeholder text |
| #6366E3 text on white | 4.62:1 | AA | Lc 71.8 | Content text, not long reading |
| #6366E3 text on black | 4.54:1 | AA | Lc -29.9 | 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 600.
-
Step 50
50
#F3F5FD
oklch(97.1% 0.011 274.9)
-
Step 100
100
#E6E9FA
oklch(93.7% 0.023 277.9)
-
Step 200
200
#D1D7F8
oklch(88.5% 0.046 277.3)
-
Step 300
300
#B3BCF7
oklch(80.9% 0.084 277.6)
-
Step 400
400
#8D97F3
oklch(70.7% 0.134 277.7)
-
Step 500
500
#737AEE
oklch(63% 0.171 277.7)
-
Step 600
600 (this color)
#6366E3
oklch(57.5% 0.186 277.8)
-
Step 700
700
#4E4EBF
oklch(49% 0.173 277.9)
-
Step 800
800
#40419B
oklch(42.8% 0.143 278)
-
Step 900
900
#35387B
oklch(37.6% 0.112 277.7)
-
Step 950
950
#1F2148
oklch(26.9% 0.071 278.2)
#6366E3 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) | #057AE7 | 0.076 |
| Deuteranopia (no green cones) | #0070E0 | 0.073 |
| Tritanopia (no blue cones) | #18839B | 0.161 |
| Achromatopsia (no color) | #757575 | 0.186 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6366E3
#6366E3
oklch(57.5% 0.186 277.8)
- #8C7800
#8C7800
oklch(57.4% 0.118 97.5)
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 #6366E3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.031
- Medium Slate Blue #7B68EE ΔE 0.040
- Royal Blue #4169E1 ΔE 0.040
- Light Indigo #6D5ACF ΔE 0.041
- Slate Blue #6A5ACD ΔE 0.042
- Neon Blue #4361EE ΔE 0.046
- Warm Blue #4B57DB ΔE 0.052
- Cornflower #6A79F7 ΔE 0.054
Use #6366E3 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.