#5B66D2
Closest named color: Dark Periwinkle (#665FD1). oklch(55.8% 0.164 275.3), rgb(91, 102, 210).
Aa
White text reads best on this color (4.91:1).
About this color
#5B66D2 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.164 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.021 away. White text reads best on it, at 4.91:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.164) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.27:1 |
| White text | 4.91:1 |
Values
| HEX | #5B66D2 |
| RGB | rgb(91, 102, 210) |
| HSL | hsl(234, 57%, 59%) |
| OKLCH | oklch(55.8% 0.164 275.3) |
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 #5B66D2 | 4.91:1 | AA | Lc -79.2 | Fine for body text |
| Black text on #5B66D2 | 4.27:1 | AA large text | Lc 30.3 | Non-text elements, placeholder text |
| #5B66D2 text on white | 4.91:1 | AA | Lc 73.7 | Content text, not long reading |
| #5B66D2 text on black | 4.27:1 | AA large text | Lc -28.0 | 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
#F3F5FC
oklch(97.1% 0.01 273.4)
-
Step 100
100
#E5E9F9
oklch(93.6% 0.022 274.7)
-
Step 200
200
#D1D8F5
oklch(88.6% 0.041 274.8)
-
Step 300
300
#B2BDF1
oklch(80.8% 0.075 275.3)
-
Step 400
400
#8C9AEA
oklch(70.8% 0.118 275.4)
-
Step 500
500
#717FE3
oklch(63.2% 0.15 275.3)
-
Step 600
600 (this color)
#5B66D2
oklch(55.8% 0.164 275.3)
-
Step 700
700
#4B54B5
oklch(49.2% 0.152 275.3)
-
Step 800
800
#3D4593
oklch(42.7% 0.127 275.3)
-
Step 900
900
#343B75
oklch(37.8% 0.098 275.5)
-
Step 950
950
#1E2345
oklch(27.1% 0.063 275.1)
#5B66D2 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) | #2B76D6 | 0.056 |
| Deuteranopia (no green cones) | #126CD0 | 0.061 |
| Tritanopia (no blue cones) | #127F92 | 0.146 |
| Achromatopsia (no color) | #717171 | 0.165 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5B66D2
#5B66D2
oklch(55.8% 0.164 275.3)
- #897200
#897200
oklch(55.8% 0.114 94.9)
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 #5B66D2, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.021
- Slate Blue #6A5ACD ΔE 0.034
- Light Indigo #6D5ACF ΔE 0.036
- Royal Blue #4169E1 ΔE 0.036
- Iris #6258C4 ΔE 0.038
- Warm Blue #4B57DB ΔE 0.047
- Neon Blue #4361EE ΔE 0.054
- Medium Slate Blue #7B68EE ΔE 0.064
Use #5B66D2 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.