#646FCF
Closest named color: Dark Periwinkle (#665FD1). oklch(57.9% 0.146 275.9), rgb(100, 111, 207).
Aa
Black text reads best on this color (4.71:1).
About this color
#646FCF is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.146 and its hue 276°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.040 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.146) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #646FCF |
| RGB | rgb(100, 111, 207) |
| HSL | hsl(234, 53%, 60%) |
| OKLCH | oklch(57.9% 0.146 275.9) |
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 #646FCF | 4.45:1 | AA large text | Lc -76.2 | Fine for body text |
| Black text on #646FCF | 4.71:1 | AA | Lc 33.4 | Non-text elements, placeholder text |
| #646FCF text on white | 4.45:1 | AA large text | Lc 70.7 | Content text, not long reading |
| #646FCF text on black | 4.71:1 | AA | Lc -31.0 | 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
#F4F5FC
oklch(97.1% 0.009 279.7)
-
Step 100
100
#E6E9F7
oklch(93.6% 0.019 276.3)
-
Step 200
200
#D2D8F2
oklch(88.6% 0.036 275.3)
-
Step 300
300
#B4BEEC
oklch(80.9% 0.066 275.3)
-
Step 400
400
#8F9BE2
oklch(70.8% 0.105 276)
-
Step 500
500
#7480DA
oklch(63.1% 0.135 276.1)
-
Step 600
600 (this color)
#646FCF
oklch(57.9% 0.146 275.9)
-
Step 700
700
#4D56AC
oklch(49.1% 0.136 275.7)
-
Step 800
800
#3F478B
oklch(42.7% 0.112 275.6)
-
Step 900
900
#353C6F
oklch(37.7% 0.087 275.5)
-
Step 950
950
#1F2341
oklch(26.9% 0.056 276.2)
#646FCF 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) | #457CD3 | 0.044 |
| Deuteranopia (no green cones) | #3973CD | 0.047 |
| Tritanopia (no blue cones) | #368495 | 0.129 |
| Achromatopsia (no color) | #777777 | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #646FCF
#646FCF
oklch(57.9% 0.146 275.9)
- #8F7900
#8F7900
oklch(57.9% 0.119 96.3)
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 #646FCF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.040
- Slate Blue #6A5ACD ΔE 0.051
- Light Indigo #6D5ACF ΔE 0.051
- Royal Blue #4169E1 ΔE 0.054
- Iris #6258C4 ΔE 0.058
- Windows Blue #3778BF ΔE 0.060
- Medium Slate Blue #7B68EE ΔE 0.061
- Cornflower #6A79F7 ΔE 0.064
Use #646FCF 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.