#5166E4
Closest named color: Royal Blue (#4169E1). oklch(56.4% 0.191 271.7), rgb(81, 102, 228).
Aa
White text reads best on this color (4.80:1).
About this color
#5166E4 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.191 and its hue 272°. Its hue sits on the cool side of the wheel. The nearest named color is Royal Blue (#4169E1), ΔE 0.018 away. White text reads best on it, at 4.80:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.191) |
| Temperature | cool |
| Nearest name | Royal Blue (#4169E1) |
| Black text | 4.37:1 |
| White text | 4.80:1 |
Values
| HEX | #5166E4 |
| RGB | rgb(81, 102, 228) |
| HSL | hsl(231, 73%, 61%) |
| OKLCH | oklch(56.4% 0.191 271.7) |
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 #5166E4 | 4.80:1 | AA | Lc -78.4 | Fine for body text |
| Black text on #5166E4 | 4.37:1 | AA large text | Lc 31.2 | Non-text elements, placeholder text |
| #5166E4 text on white | 4.80:1 | AA | Lc 72.9 | Content text, not long reading |
| #5166E4 text on black | 4.37:1 | AA large text | Lc -28.8 | 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
#F2F5FE
oklch(97% 0.012 271.3)
-
Step 100
100
#E4E9FB
oklch(93.6% 0.025 273.5)
-
Step 200
200
#CED8FA
oklch(88.5% 0.048 272.4)
-
Step 300
300
#ADBEF9
oklch(81% 0.086 271.9)
-
Step 400
400
#829AF6
oklch(70.7% 0.137 271.4)
-
Step 500
500
#657DF2
oklch(63% 0.176 271.7)
-
Step 600
600 (this color)
#5166E4
oklch(56.4% 0.191 271.7)
-
Step 700
700
#4051C3
oklch(49% 0.178 271.7)
-
Step 800
800
#35439E
oklch(42.6% 0.148 272)
-
Step 900
900
#2D3A7E
oklch(37.7% 0.116 271.6)
-
Step 950
950
#1A2349
oklch(27.1% 0.071 270.9)
#5166E4 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) | #0079E8 | 0.060 |
| Deuteranopia (no green cones) | #006CE1 | 0.051 |
| Tritanopia (no blue cones) | #00849B | 0.159 |
| Achromatopsia (no color) | #727272 | 0.192 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #5166E4
#5166E4
oklch(56.4% 0.191 271.7)
- #8E7200
#8E7200
oklch(56.3% 0.115 91.6)
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 #5166E4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Royal Blue #4169E1 ΔE 0.018
- Neon Blue #4361EE ΔE 0.026
- Warm Blue #4B57DB ΔE 0.039
- Dark Periwinkle #665FD1 ΔE 0.041
- Cerulean Blue #056EEE ΔE 0.050
- Slate Blue #6A5ACD ΔE 0.052
- Light Indigo #6D5ACF ΔE 0.053
- Azul #1D5DEC ΔE 0.055
Use #5166E4 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.