#5B66BB
Closest named color: Iris (#6258C4). oklch(54.3% 0.132 275.5), rgb(91, 102, 187).
Aa
White text reads best on this color (5.16:1).
About this color
#5B66BB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 54%, its chroma 0.132 and its hue 276°. Its hue sits on the cool side of the wheel. The nearest named color is Iris (#6258C4), ΔE 0.040 away. White text reads best on it, at 5.16:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | moderately saturated (0.132) |
| Temperature | cool |
| Nearest name | Iris (#6258C4) |
| Black text | 4.06:1 |
| White text | 5.16:1 |
Values
| HEX | #5B66BB |
| RGB | rgb(91, 102, 187) |
| HSL | hsl(233, 41%, 55%) |
| OKLCH | oklch(54.3% 0.132 275.5) |
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 #5B66BB | 5.16:1 | AA | Lc -80.8 | Fine for body text |
| Black text on #5B66BB | 4.06:1 | AA large text | Lc 28.6 | Dividers and decoration only |
| #5B66BB text on white | 5.16:1 | AA | Lc 75.4 | Fine for body text |
| #5B66BB text on black | 4.06:1 | AA large text | Lc -26.3 | 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
#E6E9F6
oklch(93.6% 0.018 275.6)
-
Step 200
200
#D2D8F0
oklch(88.5% 0.034 274.5)
-
Step 300
300
#B5BEE8
oklch(80.9% 0.06 275.5)
-
Step 400
400
#909CDC
oklch(70.8% 0.095 275.6)
-
Step 500
500
#7582D2
oklch(63.1% 0.121 275.4)
-
Step 600
600 (this color)
#5B66BB
oklch(54.3% 0.132 275.5)
-
Step 700
700
#4E58A5
oklch(49.1% 0.123 275.4)
-
Step 800
800
#404886
oklch(42.6% 0.102 275.6)
-
Step 900
900
#363D6B
oklch(37.7% 0.079 275.4)
-
Step 950
950
#20243F
oklch(27.1% 0.05 276.1)
#5B66BB 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) | #4271BE | 0.038 |
| Deuteranopia (no green cones) | #3869B9 | 0.040 |
| Tritanopia (no blue cones) | #327887 | 0.117 |
| Achromatopsia (no color) | #6D6D6D | 0.132 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5B66BB
#5B66BB
oklch(54.3% 0.132 275.5)
- #836E00
#836E00
oklch(54.2% 0.111 95.8)
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 #5B66BB, closest first.
No curated palette has a color within ΔE 0.04 of #5B66BB.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Iris #6258C4 ΔE 0.040
- French Blue #436BAD ΔE 0.040
- Dark Periwinkle #665FD1 ΔE 0.043
- Slate Blue #6A5ACD ΔE 0.047
- Light Indigo #6D5ACF ΔE 0.051
- Mid Blue #276AB3 ΔE 0.056
- Windows Blue #3778BF ΔE 0.056
- Flat Blue #3C73A8 ΔE 0.060
Use #5B66BB 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.