#166CB1
Closest named color: Mid Blue (#276AB3). oklch(52% 0.133 248.9), rgb(22, 108, 177).
Aa
White text reads best on this color (5.50:1).
About this color
#166CB1 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 52%, its chroma 0.133 and its hue 249°. 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 5.50:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | moderately saturated (0.133) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 3.81:1 |
| White text | 5.50:1 |
Values
| HEX | #166CB1 |
| RGB | rgb(22, 108, 177) |
| HSL | hsl(207, 78%, 39%) |
| OKLCH | oklch(52% 0.133 248.9) |
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 #166CB1 | 5.50:1 | AA | Lc -82.3 | Fine for body text |
| Black text on #166CB1 | 3.81:1 | AA large text | Lc 27.1 | Dividers and decoration only |
| #166CB1 text on white | 5.50:1 | AA | Lc 77.0 | Fine for body text |
| #166CB1 text on black | 3.81:1 | AA large text | Lc -24.8 | 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 700.
-
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
#C8DCF0
oklch(88.6% 0.035 248.2)
-
Step 300
300
#A1C5E9
oklch(81% 0.064 248.6)
-
Step 400
400
#6CA6DE
oklch(70.8% 0.103 248.6)
-
Step 500
500
#408ED5
oklch(63.1% 0.132 248.9)
-
Step 600
600
#1877C2
oklch(55.6% 0.142 248.7)
-
Step 700
700 (this color)
#166CB1
oklch(52% 0.133 248.9)
-
Step 800
800
#0D5188
oklch(42.6% 0.111 249.2)
-
Step 900
900
#16446D
oklch(37.8% 0.086 249.1)
-
Step 950
950
#0E2840
oklch(27% 0.055 249)
#166CB1 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) | #4A70B4 | 0.044 |
| Deuteranopia (no green cones) | #3263B0 | 0.027 |
| Tritanopia (no blue cones) | #007D86 | 0.096 |
| Achromatopsia (no color) | #696969 | 0.133 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #166CB1
#166CB1
oklch(52% 0.133 248.9)
- #925B00
#925B00
oklch(52% 0.113 69.4)
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 #166CB1, 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 0.032
- Flat Blue #3C73A8 ΔE 0.039
- Ocean Blue #03719C ΔE 0.040
- Nice Blue #107AB0 ΔE 0.041
- Muted Blue #3B719F ΔE 0.042
- Windows Blue #3778BF ΔE 0.046
- Peacock Blue #016795 ΔE 0.047
Use #166CB1 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.