#5666BB
Closest named color: French Blue (#436BAD). oklch(53.9% 0.133 273.1), rgb(86, 102, 187).
Aa
White text reads best on this color (5.23:1).
About this color
#5666BB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 54%, its chroma 0.133 and its hue 273°. Its hue sits on the cool side of the wheel. The nearest named color is French Blue (#436BAD), ΔE 0.036 away. White text reads best on it, at 5.23:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | moderately saturated (0.133) |
| Temperature | cool |
| Nearest name | French Blue (#436BAD) |
| Black text | 4.01:1 |
| White text | 5.23:1 |
Values
| HEX | #5666BB |
| RGB | rgb(86, 102, 187) |
| HSL | hsl(230, 43%, 54%) |
| OKLCH | oklch(53.9% 0.133 273.1) |
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 #5666BB | 5.23:1 | AA | Lc -81.1 | Fine for body text |
| Black text on #5666BB | 4.01:1 | AA large text | Lc 28.3 | Dividers and decoration only |
| #5666BB text on white | 5.23:1 | AA | Lc 75.8 | Fine for body text |
| #5666BB text on black | 4.01:1 | AA large text | Lc -25.9 | 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
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E6E9F6
oklch(93.6% 0.018 275.6)
-
Step 200
200
#D1D8F0
oklch(88.4% 0.034 272.8)
-
Step 300
300
#B3BFE8
oklch(80.9% 0.06 272.2)
-
Step 400
400
#8D9DDD
oklch(70.8% 0.096 273)
-
Step 500
500
#7183D3
oklch(63.1% 0.122 272.8)
-
Step 600
600 (this color)
#5666BB
oklch(53.9% 0.133 273.1)
-
Step 700
700
#4B59A6
oklch(49.1% 0.124 273.3)
-
Step 800
800
#3D4987
oklch(42.7% 0.103 273)
-
Step 900
900
#343E6C
oklch(37.8% 0.08 272.8)
-
Step 950
950
#1E243F
oklch(26.9% 0.051 273)
#5666BB 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) | #4171BE | 0.034 |
| Deuteranopia (no green cones) | #3568B9 | 0.036 |
| Tritanopia (no blue cones) | #247987 | 0.120 |
| Achromatopsia (no color) | #6C6C6C | 0.134 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5666BB
#5666BB
oklch(53.9% 0.133 273.1)
- #846C00
#846C00
oklch(53.9% 0.11 93.5)
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 #5666BB, closest first.
No curated palette has a color within ΔE 0.04 of #5666BB.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- French Blue #436BAD ΔE 0.036
- Iris #6258C4 ΔE 0.041
- Dark Periwinkle #665FD1 ΔE 0.045
- Mid Blue #276AB3 ΔE 0.049
- Slate Blue #6A5ACD ΔE 0.050
- Windows Blue #3778BF ΔE 0.053
- Light Indigo #6D5ACF ΔE 0.054
- Flat Blue #3C73A8 ΔE 0.057
Use #5666BB 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.