#0166CF
Closest named color: Mid Blue (#276AB3). oklch(52.4% 0.181 256.3), rgb(1, 102, 207).
Aa
White text reads best on this color (5.52:1).
About this color
#0166CF is a medium-dark, vivid blue. In OKLCH its lightness is 52%, its chroma 0.181 and its hue 256°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.048 away. White text reads best on it, at 5.52:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | vivid (0.181) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.80:1 |
| White text | 5.52:1 |
Values
| HEX | #0166CF |
| RGB | rgb(1, 102, 207) |
| HSL | hsl(211, 99%, 41%) |
| OKLCH | oklch(52.4% 0.181 256.3) |
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 #0166CF | 5.52:1 | AA | Lc -82.1 | Fine for body text |
| Black text on #0166CF | 3.80:1 | AA large text | Lc 27.3 | Dividers and decoration only |
| #0166CF text on white | 5.52:1 | AA | Lc 76.8 | Fine for body text |
| #0166CF text on black | 3.80:1 | AA large text | Lc -25.0 | 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
#E0EBFA
oklch(93.6% 0.024 256.1)
-
Step 200
200
#C6DBF7
oklch(88.5% 0.045 255.6)
-
Step 300
300
#9FC3F5
oklch(80.9% 0.081 256.7)
-
Step 400
400
#69A2F0
oklch(70.6% 0.13 256.5)
-
Step 500
500
#3D89EB
oklch(63.1% 0.166 256.1)
-
Step 600
600 (this color)
#0166CF
oklch(52.4% 0.181 256.3)
-
Step 700
700
#035DBD
oklch(49.1% 0.168 256.4)
-
Step 800
800
#0B4D99
oklch(42.8% 0.139 256.2)
-
Step 900
900
#14417A
oklch(37.8% 0.109 256.3)
-
Step 950
950
#0D2647
oklch(26.9% 0.069 256.4)
#0166CF 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) | #1D71D3 | 0.033 |
| Deuteranopia (no green cones) | #0061CD | 0.013 |
| Tritanopia (no blue cones) | #008091 | 0.135 |
| Achromatopsia (no color) | #696969 | 0.181 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #0166CF
#0166CF
oklch(52.4% 0.181 256.3)
- #8E6000
#8E6000
oklch(52.5% 0.11 76.2)
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 #0166CF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.048
- Royal Blue #4169E1 ΔE 0.049
- Azul #1D5DEC ΔE 0.051
- Cerulean Blue #056EEE ΔE 0.051
- Warm Blue #4B57DB ΔE 0.059
- Neon Blue #4361EE ΔE 0.063
- Windows Blue #3778BF ΔE 0.067
- French Blue #436BAD ΔE 0.068
Use #0166CF 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.