#166FFC
Closest named color: Cerulean Blue (#056EEE). oklch(58% 0.225 260.3), rgb(22, 111, 252).
Aa
Black text reads best on this color (4.71:1).
About this color
#166FFC is a medium-dark, vivid blue. In OKLCH its lightness is 58%, its chroma 0.225 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean Blue (#056EEE), ΔE 0.022 away. Black text reads best on it, at 4.71:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | vivid (0.225) |
| Temperature | cool |
| Nearest name | Cerulean Blue (#056EEE) |
| Black text | 4.71:1 |
| White text | 4.45:1 |
Values
| HEX | #166FFC |
| RGB | rgb(22, 111, 252) |
| HSL | hsl(217, 97%, 54%) |
| OKLCH | oklch(58% 0.225 260.3) |
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 #166FFC | 4.45:1 | AA large text | Lc -75.6 | Fine for body text |
| Black text on #166FFC | 4.71:1 | AA | Lc 34.0 | Non-text elements, placeholder text |
| #166FFC text on white | 4.45:1 | AA large text | Lc 70.1 | Content text, not long reading |
| #166FFC text on black | 4.71:1 | AA | Lc -31.6 | 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
#F0F6FF
oklch(97.1% 0.014 258.3)
-
Step 100
100
#DFEBFE
oklch(93.7% 0.029 259.6)
-
Step 200
200
#C4DAFF
oklch(88.4% 0.057 260.8)
-
Step 300
300
#9DC2FF
oklch(81% 0.096 260.2)
-
Step 400
400
#669FFF
oklch(70.7% 0.154 260.3)
-
Step 500
500
#3A83FF
oklch(63.1% 0.199 260.3)
-
Step 600
600 (this color)
#166FFC
oklch(58% 0.225 260.3)
-
Step 700
700
#0055D1
oklch(49.1% 0.204 260.3)
-
Step 800
800
#0346AB
oklch(42.7% 0.173 260.2)
-
Step 900
900
#0F3C87
oklch(37.6% 0.135 260.4)
-
Step 950
950
#0B244F
oklch(27% 0.085 260.5)
#166FFC 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) | #0082FF | 0.046 |
| Deuteranopia (no green cones) | #006EF9 | 0.008 |
| Tritanopia (no blue cones) | #0093AB | 0.171 |
| Achromatopsia (no color) | #777777 | 0.225 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166FFC
#166FFC
oklch(58% 0.225 260.3)
- #9F7100
#9F7100
oklch(58% 0.12 80.3)
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 #166FFC, closest first.
No curated palette has a color within ΔE 0.04 of #166FFC.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean Blue #056EEE ΔE 0.022
- Bright Blue #0165FC ΔE 0.025
- Clear Blue #247AFD ΔE 0.029
- Neon Blue #4361EE ΔE 0.043
- Royal Blue #4169E1 ΔE 0.047
- Azul #1D5DEC ΔE 0.048
- Electric Blue #0652FF ΔE 0.065
- Warm Blue #4B57DB ΔE 0.077
Use #166FFC 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.