#5B66CD
Closest named color: Dark Periwinkle (#665FD1). oklch(55.4% 0.158 275.4), rgb(91, 102, 205).
Aa
White text reads best on this color (4.96:1).
About this color
#5B66CD is a medium-dark, vivid blue. In OKLCH its lightness is 55%, its chroma 0.158 and its hue 275°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Periwinkle (#665FD1), ΔE 0.023 away. White text reads best on it, at 4.96:1.
| Hue family | Blues |
| Lightness | medium-dark (55%) |
| Chroma | vivid (0.158) |
| Temperature | cool |
| Nearest name | Dark Periwinkle (#665FD1) |
| Black text | 4.22:1 |
| White text | 4.96:1 |
Values
| HEX | #5B66CD |
| RGB | rgb(91, 102, 205) |
| HSL | hsl(234, 53%, 58%) |
| OKLCH | oklch(55.4% 0.158 275.4) |
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 #5B66CD | 4.96:1 | AA | Lc -79.5 | Fine for body text |
| Black text on #5B66CD | 4.22:1 | AA large text | Lc 29.9 | Dividers and decoration only |
| #5B66CD text on white | 4.96:1 | AA | Lc 74.1 | Content text, not long reading |
| #5B66CD text on black | 4.22:1 | AA large text | Lc -27.6 | 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
#E6E9F8
oklch(93.6% 0.02 276.9)
-
Step 200
200
#D1D8F4
oklch(88.6% 0.039 274.4)
-
Step 300
300
#B3BEEF
oklch(81% 0.07 274.9)
-
Step 400
400
#8D9AE7
oklch(70.7% 0.114 275.8)
-
Step 500
500
#727FE0
oklch(63.1% 0.146 275.7)
-
Step 600
600 (this color)
#5B66CD
oklch(55.4% 0.158 275.4)
-
Step 700
700
#4C55B2
oklch(49.2% 0.146 275.5)
-
Step 800
800
#3E4690
oklch(42.8% 0.121 275.4)
-
Step 900
900
#343B73
oklch(37.6% 0.095 275.5)
-
Step 950
950
#1E2343
oklch(26.9% 0.06 275)
#5B66CD 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) | #3175D1 | 0.052 |
| Deuteranopia (no green cones) | #1F6BCB | 0.056 |
| Tritanopia (no blue cones) | #1D7D90 | 0.138 |
| Achromatopsia (no color) | #707070 | 0.158 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5B66CD
#5B66CD
oklch(55.4% 0.158 275.4)
- #877100
#877100
oklch(55.3% 0.114 95.5)
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 #5B66CD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Periwinkle #665FD1 ΔE 0.023
- Slate Blue #6A5ACD ΔE 0.034
- Iris #6258C4 ΔE 0.036
- Light Indigo #6D5ACF ΔE 0.037
- Royal Blue #4169E1 ΔE 0.041
- Warm Blue #4B57DB ΔE 0.050
- Neon Blue #4361EE ΔE 0.060
- French Blue #436BAD ΔE 0.062
Use #5B66CD 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.