#166CB8
Closest named color: Mid Blue (#276AB3). oklch(52.4% 0.142 251), rgb(22, 108, 184).
Aa
White text reads best on this color (5.42:1).
About this color
#166CB8 is a medium-dark, vivid blue. In OKLCH its lightness is 52%, its chroma 0.142 and its hue 251°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.011 away. White text reads best on it, at 5.42:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | vivid (0.142) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.87:1 |
| White text | 5.42:1 |
Values
| HEX | #166CB8 |
| RGB | rgb(22, 108, 184) |
| HSL | hsl(208, 79%, 40%) |
| OKLCH | oklch(52.4% 0.142 251) |
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 #166CB8 | 5.42:1 | AA | Lc -81.9 | Fine for body text |
| Black text on #166CB8 | 3.87:1 | AA large text | Lc 27.5 | Dividers and decoration only |
| #166CB8 text on white | 5.42:1 | AA | Lc 76.5 | Fine for body text |
| #166CB8 text on black | 3.87:1 | AA large text | Lc -25.2 | 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
#E1EBF6
oklch(93.6% 0.018 250.6)
-
Step 200
200
#C8DBF0
oklch(88.4% 0.036 250.9)
-
Step 300
300
#A3C4E9
oklch(80.9% 0.064 251.5)
-
Step 400
400
#6FA5DE
oklch(70.7% 0.102 250.7)
-
Step 500
500
#468DD5
oklch(63.1% 0.13 250.9)
-
Step 600
600 (this color)
#166CB8
oklch(52.4% 0.142 251)
-
Step 700
700
#1563A8
oklch(49.2% 0.131 250.8)
-
Step 800
800
#155188
oklch(42.8% 0.109 250.7)
-
Step 900
900
#1A436D
oklch(37.6% 0.085 251.6)
-
Step 950
950
#102840
oklch(27.1% 0.054 250.5)
#166CB8 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) | #4671BB | 0.040 |
| Deuteranopia (no green cones) | #2A63B7 | 0.025 |
| Tritanopia (no blue cones) | #007E89 | 0.103 |
| Achromatopsia (no color) | #6A6A6A | 0.142 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166CB8
#166CB8
oklch(52.4% 0.142 251)
- #925D00
#925D00
oklch(52.4% 0.113 71.1)
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 #166CB8, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.011
- French Blue #436BAD ΔE 0.035
- Windows Blue #3778BF ΔE 0.043
- Flat Blue #3C73A8 ΔE 0.044
- Nice Blue #107AB0 ΔE 0.044
- Muted Blue #3B719F ΔE 0.051
- Ocean Blue #03719C ΔE 0.051
- Peacock Blue #016795 ΔE 0.057
Use #166CB8 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.