#166BEB
Closest named color: Cerulean Blue (#056EEE). oklch(55.9% 0.208 259.7), rgb(22, 107, 235).
Aa
White text reads best on this color (4.84:1).
About this color
#166BEB is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.208 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean Blue (#056EEE), ΔE 0.008 away. White text reads best on it, at 4.84:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.208) |
| Temperature | cool |
| Nearest name | Cerulean Blue (#056EEE) |
| Black text | 4.33:1 |
| White text | 4.84:1 |
Values
| HEX | #166BEB |
| RGB | rgb(22, 107, 235) |
| HSL | hsl(216, 84%, 50%) |
| OKLCH | oklch(55.9% 0.208 259.7) |
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 #166BEB | 4.84:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #166BEB | 4.33:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #166BEB text on white | 4.84:1 | AA | Lc 72.8 | Content text, not long reading |
| #166BEB text on black | 4.33:1 | AA large text | Lc -28.9 | 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
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#DFEBFD
oklch(93.6% 0.028 258.4)
-
Step 200
200
#C5DAFC
oklch(88.4% 0.052 260)
-
Step 300
300
#9DC2FE
oklch(80.9% 0.094 259.9)
-
Step 400
400
#66A0FD
oklch(70.7% 0.15 259.4)
-
Step 500
500
#3B84FB
oklch(63.1% 0.192 259.8)
-
Step 600
600 (this color)
#166BEB
oklch(55.9% 0.208 259.7)
-
Step 700
700
#0457CC
oklch(49.1% 0.195 259.8)
-
Step 800
800
#0B48A5
oklch(42.7% 0.161 259.9)
-
Step 900
900
#133E82
oklch(37.7% 0.124 259.6)
-
Step 950
950
#0C254C
oklch(27% 0.079 259.2)
#166BEB 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) | #007BEF | 0.039 |
| Deuteranopia (no green cones) | #0069E9 | 0.009 |
| Tritanopia (no blue cones) | #008BA1 | 0.157 |
| Achromatopsia (no color) | #727272 | 0.208 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166BEB
#166BEB
oklch(55.9% 0.208 259.7)
- #986B00
#986B00
oklch(56% 0.116 79.5)
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 #166BEB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean Blue #056EEE ΔE 0.008
- Bright Blue #0165FC ΔE 0.030
- Royal Blue #4169E1 ΔE 0.031
- Azul #1D5DEC ΔE 0.032
- Neon Blue #4361EE ΔE 0.035
- Clear Blue #247AFD ΔE 0.047
- Warm Blue #4B57DB ΔE 0.059
- Electric Blue #0652FF ΔE 0.063
Use #166BEB 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.