#166DCC
Closest named color: Mid Blue (#276AB3). oklch(54% 0.166 255.1), rgb(22, 109, 204).
Aa
White text reads best on this color (5.13:1).
About this color
#166DCC is a medium-dark, vivid blue. In OKLCH its lightness is 54%, its chroma 0.166 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.039 away. White text reads best on it, at 5.13:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | vivid (0.166) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 4.09:1 |
| White text | 5.13:1 |
Values
| HEX | #166DCC |
| RGB | rgb(22, 109, 204) |
| HSL | hsl(211, 81%, 44%) |
| OKLCH | oklch(54% 0.166 255.1) |
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 #166DCC | 5.13:1 | AA | Lc -80.2 | Fine for body text |
| Black text on #166DCC | 4.09:1 | AA large text | Lc 29.3 | Dividers and decoration only |
| #166DCC text on white | 5.13:1 | AA | Lc 74.8 | Content text, not long reading |
| #166DCC text on black | 4.09:1 | AA large text | Lc -27.0 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E0EBF9
oklch(93.6% 0.022 254.4)
-
Step 200
200
#C7DBF5
oklch(88.5% 0.042 255)
-
Step 300
300
#A0C3F1
oklch(80.8% 0.076 255.4)
-
Step 400
400
#6CA3EA
oklch(70.7% 0.12 255.3)
-
Step 500
500
#428AE3
oklch(63% 0.153 255.2)
-
Step 600
600 (this color)
#166DCC
oklch(54% 0.166 255.1)
-
Step 700
700
#0D5FB5
oklch(49.1% 0.154 255)
-
Step 800
800
#114E93
oklch(42.7% 0.128 255.2)
-
Step 900
900
#174275
oklch(37.8% 0.099 254.9)
-
Step 950
950
#0F2744
oklch(27% 0.062 254.6)
#166DCC 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) | #3776D0 | 0.035 |
| Deuteranopia (no green cones) | #0066CA | 0.021 |
| Tritanopia (no blue cones) | #008492 | 0.125 |
| Achromatopsia (no color) | #6E6E6E | 0.166 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166DCC
#166DCC
oklch(54% 0.166 255.1)
- #956300
#956300
oklch(54% 0.114 74.6)
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 #166DCC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.039
- Windows Blue #3778BF ΔE 0.046
- Royal Blue #4169E1 ΔE 0.046
- Cerulean Blue #056EEE ΔE 0.052
- French Blue #436BAD ΔE 0.055
- Nice Blue #107AB0 ΔE 0.062
- Azul #1D5DEC ΔE 0.064
- Flat Blue #3C73A8 ΔE 0.066
Use #166DCC 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.