#166EE1
Closest named color: Cerulean Blue (#056EEE). oklch(55.7% 0.192 257.9), rgb(22, 110, 225).
Aa
White text reads best on this color (4.82:1).
About this color
#166EE1 is a medium-dark, vivid blue. In OKLCH its lightness is 56%, its chroma 0.192 and its hue 258°. Its hue sits on the cool side of the wheel. The nearest named color is Cerulean Blue (#056EEE), ΔE 0.020 away. White text reads best on it, at 4.82:1.
| Hue family | Blues |
| Lightness | medium-dark (56%) |
| Chroma | vivid (0.192) |
| Temperature | cool |
| Nearest name | Cerulean Blue (#056EEE) |
| Black text | 4.35:1 |
| White text | 4.82:1 |
Values
| HEX | #166EE1 |
| RGB | rgb(22, 110, 225) |
| HSL | hsl(214, 82%, 48%) |
| OKLCH | oklch(55.7% 0.192 257.9) |
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 #166EE1 | 4.82:1 | AA | Lc -78.2 | Fine for body text |
| Black text on #166EE1 | 4.35:1 | AA large text | Lc 31.3 | Non-text elements, placeholder text |
| #166EE1 text on white | 4.82:1 | AA | Lc 72.8 | Content text, not long reading |
| #166EE1 text on black | 4.35:1 | 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
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E0EBFB
oklch(93.7% 0.025 257.6)
-
Step 200
200
#C6DBF9
oklch(88.5% 0.047 257.3)
-
Step 300
300
#9EC3F9
oklch(81% 0.087 257.7)
-
Step 400
400
#68A1F6
oklch(70.7% 0.139 258.2)
-
Step 500
500
#3C87F2
oklch(63.1% 0.177 257.9)
-
Step 600
600 (this color)
#166EE1
oklch(55.7% 0.192 257.9)
-
Step 700
700
#045BC3
oklch(49.2% 0.178 257.9)
-
Step 800
800
#0B4B9E
oklch(42.8% 0.148 257.9)
-
Step 900
900
#133F7D
oklch(37.6% 0.116 258)
-
Step 950
950
#0D2649
oklch(27.1% 0.072 257.4)
#166EE1 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) | #1B7BE5 | 0.034 |
| Deuteranopia (no green cones) | #006ADF | 0.013 |
| Tritanopia (no blue cones) | #008A9D | 0.145 |
| Achromatopsia (no color) | #727272 | 0.192 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166EE1
#166EE1
oklch(55.7% 0.192 257.9)
- #996900
#996900
oklch(55.7% 0.116 77.3)
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 #166EE1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cerulean Blue #056EEE ΔE 0.020
- Royal Blue #4169E1 ΔE 0.028
- Azul #1D5DEC ΔE 0.044
- Neon Blue #4361EE ΔE 0.045
- Bright Blue #0165FC ΔE 0.047
- Clear Blue #247AFD ΔE 0.052
- Warm Blue #4B57DB ΔE 0.061
- Windows Blue #3778BF ΔE 0.065
Use #166EE1 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.