#178BB1
Closest named color: Blue NCS (#118AB2). oklch(59.5% 0.11 226.9), rgb(23, 139, 177).
Aa
Black text reads best on this color (5.36:1).
About this color
#178BB1 is a medium-dark, moderately saturated teal or cyan. In OKLCH its lightness is 60%, its chroma 0.110 and its hue 227°. Its hue sits on the cool side of the wheel. The nearest named color is Blue NCS (#118AB2), ΔE 0.004 away. Black text reads best on it, at 5.36:1.
| Hue family | Teals and cyans |
| Lightness | medium-dark (60%) |
| Chroma | moderately saturated (0.110) |
| Temperature | cool |
| Nearest name | Blue NCS (#118AB2) |
| Black text | 5.36:1 |
| White text | 3.91:1 |
Values
| HEX | #178BB1 |
| RGB | rgb(23, 139, 177) |
| HSL | hsl(195, 77%, 39%) |
| OKLCH | oklch(59.5% 0.11 226.9) |
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 #178BB1 | 3.91:1 | AA large text | Lc -71.6 | Content text, not long reading |
| Black text on #178BB1 | 5.36:1 | AA | Lc 38.0 | Non-text elements, placeholder text |
| #178BB1 text on white | 3.91:1 | AA large text | Lc 66.1 | Content text, not long reading |
| #178BB1 text on black | 5.36:1 | AA | Lc -35.6 | Non-text elements, placeholder text |
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 500.
-
Step 50
50
#F1F6F9
oklch(97% 0.007 233.6)
-
Step 100
100
#E0ECF2
oklch(93.6% 0.015 229)
-
Step 200
200
#C6DEE9
oklch(88.6% 0.03 227)
-
Step 300
300
#9DC8DC
oklch(80.9% 0.053 228)
-
Step 400
400
#62ACCA
oklch(70.8% 0.086 226.3)
-
Step 500
500 (this color)
#178BB1
oklch(59.5% 0.11 226.9)
-
Step 600
600
#007FA4
oklch(55.6% 0.108 227.1)
-
Step 700
700
#006B8A
oklch(49.2% 0.095 226.5)
-
Step 800
800
#005772
oklch(42.6% 0.083 227.6)
-
Step 900
900
#03495F
oklch(37.8% 0.071 226.7)
-
Step 950
950
#082B37
oklch(27.1% 0.045 225.2)
#178BB1 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) | #7788B3 | 0.081 |
| Deuteranopia (no green cones) | #637BB1 | 0.069 |
| Tritanopia (no blue cones) | #009698 | 0.058 |
| Achromatopsia (no color) | #818181 | 0.110 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178BB1
#178BB1
oklch(59.5% 0.11 226.9)
- #B36942
#B36942
oklch(59.5% 0.109 47.6)
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 #178BB1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue NCS #118AB2 ΔE 0.004
- Teal Blue #01889F ΔE 0.029
- Steel Blue #4682B4 ΔE 0.036
- Cool Blue #4984B8 ΔE 0.038
- Off Blue #5684AE ΔE 0.043
- Dusty Blue #5A86AD ΔE 0.046
- Water Blue #0E87CC ΔE 0.046
- Cerulean #457B9D ΔE 0.050
Use #178BB1 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.