#5B66C2
Closest named color: Dark Periwinkle (#665FD1). oklch(54.7% 0.142 275.5), rgb(91, 102, 194).
Aa
White text reads best on this color (5.09:1).
About this color
#5B66C2 is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.142 and its hue 276°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.034 away. White text reads best on it, at 5.09:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.142) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.12:1 |
| White text | 5.09:1 |
Values
| HEX | #5B66C2 |
| RGB | rgb(91, 102, 194) |
| HSL | hsl(234, 46%, 56%) |
| OKLCH | oklch(54.7% 0.142 275.5) |
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 #5B66C2 | 5.09:1 | AA | Lc -80.3 | Fine for body text |
| Black text on #5B66C2 | 4.12:1 | AA large text | Lc 29.1 | Dividers and decoration only |
| #5B66C2 text on white | 5.09:1 | AA | Lc 74.9 | Content text, not long reading |
| #5B66C2 text on black | 4.12:1 | AA large text | Lc -26.8 | 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
#F4F5FB
oklch(97.1% 0.008 278.6)
-
Step 100
100
#E6E9F7
oklch(93.6% 0.019 276.3)
-
Step 200
200
#D2D8F1
oklch(88.5% 0.035 274.9)
-
Step 300
300
#B4BEEB
oklch(80.9% 0.065 275.1)
-
Step 400
400
#8E9BE0
oklch(70.6% 0.102 275.3)
-
Step 500
500
#7481D8
oklch(63.1% 0.131 275.6)
-
Step 600
600 (this color)
#5B66C2
oklch(54.7% 0.142 275.5)
-
Step 700
700
#4D57AA
oklch(49.1% 0.132 275.3)
-
Step 800
800
#3F478A
oklch(42.6% 0.11 275.6)
-
Step 900
900
#353C6E
oklch(37.6% 0.086 275.5)
-
Step 950
950
#1F2441
oklch(27.1% 0.054 274.8)
#5B66C2 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) | #3C73C5 | 0.044 |
| Deuteranopia (no green cones) | #306AC0 | 0.046 |
| Tritanopia (no blue cones) | #2C7A8B | 0.124 |
| Achromatopsia (no color) | #6E6E6E | 0.142 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5B66C2
#5B66C2
oklch(54.7% 0.142 275.5)
- #856F00
#856F00
oklch(54.7% 0.112 95.2)
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 #5B66C2, closest first.
No curated palette has a color within ΔE 0.04 of #5B66C2.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.034
- Iris #6258C4 ΔE 0.036
- Slate Blue #6A5ACD ΔE 0.040
- Light Indigo #6D5ACF ΔE 0.044
- French Blue #436BAD ΔE 0.048
- Royal Blue #4169E1 ΔE 0.055
- Windows Blue #3778BF ΔE 0.058
- Mid Blue #276AB3 ΔE 0.060
Use #5B66C2 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.