#646ADC
Closest named color: Dark Periwinkle (#665FD1). oklch(57.8% 0.171 277.4), rgb(100, 106, 220).
Aa
Black text reads best on this color (4.63:1).
About this color
#646ADC is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.171 and its hue 277°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.030 away. Black text reads best on it, at 4.63:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.171) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.63:1 |
| White text | 4.52:1 |
Values
| HEX | #646ADC |
| RGB | rgb(100, 106, 220) |
| HSL | hsl(237, 63%, 63%) |
| OKLCH | oklch(57.8% 0.171 277.4) |
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 #646ADC | 4.52:1 | AA | Lc -76.6 | Fine for body text |
| Black text on #646ADC | 4.63:1 | AA | Lc 32.9 | Non-text elements, placeholder text |
| #646ADC text on white | 4.52:1 | AA | Lc 71.2 | Content text, not long reading |
| #646ADC text on black | 4.63:1 | AA | Lc -30.5 | Non-text elements, placeholder text |
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
#E6E9F9
oklch(93.6% 0.022 277.5)
-
Step 200
200
#D2D7F6
oklch(88.5% 0.043 278.2)
-
Step 300
300
#B4BDF3
oklch(81% 0.077 277.2)
-
Step 400
400
#8E98EC
oklch(70.6% 0.123 277.6)
-
Step 500
500
#747DE6
oklch(63.2% 0.156 277.3)
-
Step 600
600 (this color)
#646ADC
oklch(57.8% 0.171 277.4)
-
Step 700
700
#4E51B8
oklch(49% 0.159 277.5)
-
Step 800
800
#404395
oklch(42.7% 0.132 277.7)
-
Step 900
900
#353A77
oklch(37.8% 0.103 276.8)
-
Step 950
950
#1F2245
oklch(26.9% 0.064 277.4)
#646ADC 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) | #2B7BE0 | 0.063 |
| Deuteranopia (no green cones) | #1571DA | 0.068 |
| Tritanopia (no blue cones) | #288499 | 0.150 |
| Achromatopsia (no color) | #767676 | 0.171 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #646ADC
#646ADC
oklch(57.8% 0.171 277.4)
- #8E7900
#8E7900
oklch(57.8% 0.119 96.9)
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 #646ADC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.030
- Light Indigo #6D5ACF ΔE 0.042
- Slate Blue #6A5ACD ΔE 0.042
- Royal Blue #4169E1 ΔE 0.043
- Medium Slate Blue #7B68EE ΔE 0.043
- Cornflower #6A79F7 ΔE 0.053
- Iris #6258C4 ΔE 0.055
- Neon Blue #4361EE ΔE 0.056
Use #646ADC 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.