#166DBE
Closest named color: Mid Blue (#276AB3). oklch(53% 0.148 252.1), rgb(22, 109, 190).
Aa
White text reads best on this color (5.29:1).
About this color
#166DBE is a medium-dark, vivid blue. In OKLCH its lightness is 53%, its chroma 0.148 and its hue 252°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.018 away. White text reads best on it, at 5.29:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | vivid (0.148) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.96:1 |
| White text | 5.29:1 |
Values
| HEX | #166DBE |
| RGB | rgb(22, 109, 190) |
| HSL | hsl(209, 79%, 42%) |
| OKLCH | oklch(53% 0.148 252.1) |
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 #166DBE | 5.29:1 | AA | Lc -81.2 | Fine for body text |
| Black text on #166DBE | 3.96:1 | AA large text | Lc 28.3 | Dividers and decoration only |
| #166DBE text on white | 5.29:1 | AA | Lc 75.8 | Fine for body text |
| #166DBE text on black | 3.96:1 | AA large text | Lc -25.9 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF7
oklch(93.6% 0.019 252.9)
-
Step 200
200
#C8DBF2
oklch(88.4% 0.038 253.2)
-
Step 300
300
#A2C4EB
oklch(80.9% 0.066 252.1)
-
Step 400
400
#6EA4E1
oklch(70.6% 0.107 252.3)
-
Step 500
500
#458CD9
oklch(63% 0.137 252.4)
-
Step 600
600 (this color)
#166DBE
oklch(53% 0.148 252.1)
-
Step 700
700
#1262AC
oklch(49.2% 0.138 252.1)
-
Step 800
800
#14508B
oklch(42.7% 0.114 252.3)
-
Step 900
900
#18436F
oklch(37.7% 0.089 251.8)
-
Step 950
950
#102741
oklch(26.9% 0.057 253.1)
#166DBE 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) | #4373C1 | 0.038 |
| Deuteranopia (no green cones) | #2365BC | 0.021 |
| Tritanopia (no blue cones) | #00818C | 0.110 |
| Achromatopsia (no color) | #6B6B6B | 0.148 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166DBE
#166DBE
oklch(53% 0.148 252.1)
- #935F00
#935F00
oklch(52.9% 0.113 72.3)
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 #166DBE, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.018
- French Blue #436BAD ΔE 0.039
- Windows Blue #3778BF ΔE 0.040
- Nice Blue #107AB0 ΔE 0.047
- Flat Blue #3C73A8 ΔE 0.048
- Muted Blue #3B719F ΔE 0.057
- Ocean Blue #03719C ΔE 0.059
- Royal Blue #4169E1 ΔE 0.065
Use #166DBE 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.