#166FB5
Closest named color: Mid Blue (#276AB3). oklch(52.9% 0.135 248.5), rgb(22, 111, 181).
Aa
White text reads best on this color (5.28:1).
About this color
#166FB5 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 53%, its chroma 0.135 and its hue 249°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.015 away. White text reads best on it, at 5.28:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | moderately saturated (0.135) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.97:1 |
| White text | 5.28:1 |
Values
| HEX | #166FB5 |
| RGB | rgb(22, 111, 181) |
| HSL | hsl(206, 78%, 40%) |
| OKLCH | oklch(52.9% 0.135 248.5) |
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 #166FB5 | 5.28:1 | AA | Lc -81.1 | Fine for body text |
| Black text on #166FB5 | 3.97:1 | AA large text | Lc 28.3 | Dividers and decoration only |
| #166FB5 text on white | 5.28:1 | AA | Lc 75.8 | Fine for body text |
| #166FB5 text on black | 3.97:1 | AA large text | Lc -26.0 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#E1EBF5
oklch(93.5% 0.017 248)
-
Step 200
200
#C9DCEF
oklch(88.6% 0.033 248.2)
-
Step 300
300
#A3C5E7
oklch(81% 0.061 248.6)
-
Step 400
400
#6FA6DB
oklch(70.8% 0.097 248.5)
-
Step 500
500
#468ED1
oklch(63.1% 0.125 249)
-
Step 600
600 (this color)
#166FB5
oklch(52.9% 0.135 248.5)
-
Step 700
700
#1264A4
oklch(49.2% 0.126 248.5)
-
Step 800
800
#145285
oklch(42.8% 0.104 248.5)
-
Step 900
900
#19446A
oklch(37.7% 0.081 248.4)
-
Step 950
950
#10283E
oklch(27% 0.051 248.4)
#166FB5 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) | #4D73B8 | 0.046 |
| Deuteranopia (no green cones) | #3465B4 | 0.030 |
| Tritanopia (no blue cones) | #008089 | 0.097 |
| Achromatopsia (no color) | #6C6C6C | 0.135 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166FB5
#166FB5
oklch(52.9% 0.135 248.5)
- #965D00
#965D00
oklch(52.9% 0.116 68.9)
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 #166FB5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.015
- French Blue #436BAD ΔE 0.032
- Nice Blue #107AB0 ΔE 0.034
- Flat Blue #3C73A8 ΔE 0.036
- Windows Blue #3778BF ΔE 0.038
- Muted Blue #3B719F ΔE 0.042
- Ocean Blue #03719C ΔE 0.043
- Peacock Blue #016795 ΔE 0.054
Use #166FB5 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.