#6566E9
Closest named color: Medium Slate Blue (#7B68EE). oklch(58.1% 0.193 278.2), rgb(101, 102, 233).
Aa
Black text reads best on this color (4.63:1).
About this color
#6566E9 is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.193 and its hue 278°. Its hue sits on the cool side of the wheel. The nearest named color is Medium Slate Blue (#7B68EE), ΔE 0.034 away. Black text reads best on it, at 4.63:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.193) |
| Temperature | cool |
| Nearest name | Medium Slate Blue (#7B68EE) |
| Black text | 4.63:1 |
| White text | 4.53:1 |
Values
| HEX | #6566E9 |
| RGB | rgb(101, 102, 233) |
| HSL | hsl(240, 75%, 65%) |
| OKLCH | oklch(58.1% 0.193 278.2) |
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 #6566E9 | 4.53:1 | AA | Lc -76.6 | Fine for body text |
| Black text on #6566E9 | 4.63:1 | AA | Lc 33.0 | Non-text elements, placeholder text |
| #6566E9 text on white | 4.53:1 | AA | Lc 71.1 | Content text, not long reading |
| #6566E9 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
#E5E9FB
oklch(93.6% 0.025 275.9)
-
Step 200
200
#D1D7FA
oklch(88.6% 0.049 277.7)
-
Step 300
300
#B3BCF9
oklch(81% 0.087 277.8)
-
Step 400
400
#8D96F6
oklch(70.7% 0.14 278.1)
-
Step 500
500
#7479F2
oklch(63.2% 0.178 278.2)
-
Step 600
600 (this color)
#6566E9
oklch(58.1% 0.193 278.2)
-
Step 700
700
#4E4DC3
oklch(49.2% 0.179 277.9)
-
Step 800
800
#40409E
oklch(42.8% 0.149 278.1)
-
Step 900
900
#36377D
oklch(37.7% 0.116 278.7)
-
Step 950
950
#1F2149
oklch(27% 0.073 278.2)
#6566E9 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) | #007CED | 0.080 |
| Deuteranopia (no green cones) | #0071E6 | 0.075 |
| Tritanopia (no blue cones) | #15859E | 0.168 |
| Achromatopsia (no color) | #767676 | 0.194 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #6566E9
#6566E9
oklch(58.1% 0.193 278.2)
- #8E7A00
#8E7A00
oklch(58.1% 0.12 97.7)
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 #6566E9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Medium Slate Blue #7B68EE ΔE 0.034
- Dark Periwinkle #665FD1 ΔE 0.039
- Royal Blue #4169E1 ΔE 0.045
- Neon Blue #4361EE ΔE 0.046
- Light Indigo #6D5ACF ΔE 0.047
- Slate Blue #6A5ACD ΔE 0.049
- Cornflower #6A79F7 ΔE 0.049
- Warm Blue #4B57DB ΔE 0.057
Use #6566E9 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.