#178BCF
Closest named color: Water Blue (#0E87CC). oklch(61.1% 0.139 242.3), rgb(23, 139, 207).
Aa
Black text reads best on this color (5.63:1).
About this color
#178BCF is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.139 and its hue 242°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.012 away. Black text reads best on it, at 5.63:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.139) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.63:1 |
| White text | 3.72:1 |
Values
| HEX | #178BCF |
| RGB | rgb(23, 139, 207) |
| HSL | hsl(202, 80%, 45%) |
| OKLCH | oklch(61.1% 0.139 242.3) |
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 #178BCF | 3.72:1 | AA large text | Lc -69.8 | Content text, not long reading |
| Black text on #178BCF | 5.63:1 | AA | Lc 39.8 | Non-text elements, placeholder text |
| #178BCF text on white | 3.72:1 | AA large text | Lc 64.3 | Content text, not long reading |
| #178BCF text on black | 5.63:1 | AA | Lc -37.3 | 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
#F0F6FB
oklch(97% 0.009 242.8)
-
Step 100
100
#DFECF6
oklch(93.6% 0.019 240.7)
-
Step 200
200
#C4DDF1
oklch(88.5% 0.038 242.2)
-
Step 300
300
#9AC7E9
oklch(80.9% 0.068 241.3)
-
Step 400
400
#5EA8DF
oklch(70.6% 0.11 242.6)
-
Step 500
500 (this color)
#178BCF
oklch(61.1% 0.139 242.3)
-
Step 600
600
#007ABA
oklch(55.6% 0.133 242.5)
-
Step 700
700
#00679D
oklch(49.2% 0.117 242)
-
Step 800
800
#005481
oklch(42.7% 0.101 241.9)
-
Step 900
900
#00466D
oklch(37.8% 0.09 242.2)
-
Step 950
950
#062940
oklch(27% 0.058 242.5)
#178BCF 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) | #6A8DD2 | 0.064 |
| Deuteranopia (no green cones) | #517DCE | 0.048 |
| Tritanopia (no blue cones) | #009CA3 | 0.095 |
| Achromatopsia (no color) | #848484 | 0.139 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178BCF
#178BCF
oklch(61.1% 0.139 242.3)
- #BD6D04
#BD6D04
oklch(61.1% 0.139 62.3)
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 #178BCF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.012
- Cool Blue #4984B8 ΔE 0.042
- Dark Sky Blue #448EE4 ΔE 0.043
- Blue NCS #118AB2 ΔE 0.045
- Steel Blue #4682B4 ΔE 0.046
- Windows Blue #3778BF ΔE 0.053
- Off Blue #5684AE ΔE 0.060
- Nice Blue #107AB0 ΔE 0.062
Use #178BCF 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.