#5B73CF
Closest named color: Windows Blue (#3778BF). oklch(58.1% 0.144 270.4), rgb(91, 115, 207).
Aa
Black text reads best on this color (4.79:1).
About this color
#5B73CF is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.144 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.047 away. Black text reads best on it, at 4.79:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.144) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.79:1 |
| White text | 4.37:1 |
Values
| HEX | #5B73CF |
| RGB | rgb(91, 115, 207) |
| HSL | hsl(228, 55%, 58%) |
| OKLCH | oklch(58.1% 0.144 270.4) |
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 #5B73CF | 4.37:1 | AA large text | Lc -75.6 | Fine for body text |
| Black text on #5B73CF | 4.79:1 | AA | Lc 33.9 | Non-text elements, placeholder text |
| #5B73CF text on white | 4.37:1 | AA large text | Lc 70.1 | Content text, not long reading |
| #5B73CF text on black | 4.79:1 | AA | Lc -31.5 | Non-text elements, placeholder text |
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
#E5EAF7
oklch(93.7% 0.018 269.1)
-
Step 200
200
#D0D9F2
oklch(88.6% 0.036 269.9)
-
Step 300
300
#B0BFEB
oklch(80.8% 0.065 270.2)
-
Step 400
400
#889DE1
oklch(70.7% 0.103 270.5)
-
Step 500
500
#6B83D9
oklch(63% 0.133 270.5)
-
Step 600
600 (this color)
#5B73CF
oklch(58.1% 0.144 270.4)
-
Step 700
700
#4559AC
oklch(49.1% 0.134 270.6)
-
Step 800
800
#38498B
oklch(42.6% 0.111 270.3)
-
Step 900
900
#303E6F
oklch(37.7% 0.086 269.9)
-
Step 950
950
#1C2441
oklch(26.9% 0.055 270.7)
#5B73CF 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) | #4A7ED2 | 0.031 |
| Deuteranopia (no green cones) | #3B74CD | 0.033 |
| Tritanopia (no blue cones) | #138797 | 0.128 |
| Achromatopsia (no color) | #797979 | 0.144 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5B73CF
#5B73CF
oklch(58.1% 0.144 270.4)
- #967700
#967700
oklch(58.3% 0.119 90.5)
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 #5B73CF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.047
- Dark Periwinkle #665FD1 ΔE 0.051
- Royal Blue #4169E1 ΔE 0.051
- Slate Blue #6A5ACD ΔE 0.062
- Light Indigo #6D5ACF ΔE 0.064
- French Blue #436BAD ΔE 0.064
- Cornflower #6A79F7 ΔE 0.065
- Soft Blue #6488EA ΔE 0.066
Use #5B73CF 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.