#178CC4
Closest named color: Water Blue (#0E87CC). oklch(60.7% 0.127 236.9), rgb(23, 140, 196).
Aa
Black text reads best on this color (5.58:1).
About this color
#178CC4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.127 and its hue 237°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.021 away. Black text reads best on it, at 5.58:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.127) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.58:1 |
| White text | 3.76:1 |
Values
| HEX | #178CC4 |
| RGB | rgb(23, 140, 196) |
| HSL | hsl(199, 79%, 43%) |
| OKLCH | oklch(60.7% 0.127 236.9) |
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 #178CC4 | 3.76:1 | AA large text | Lc -70.1 | Content text, not long reading |
| Black text on #178CC4 | 5.58:1 | AA | Lc 39.4 | Non-text elements, placeholder text |
| #178CC4 text on white | 3.76:1 | AA large text | Lc 64.6 | Content text, not long reading |
| #178CC4 text on black | 5.58:1 | AA | Lc -37.0 | 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
#F0F6FA
oklch(97% 0.008 236.6)
-
Step 100
100
#DFECF5
oklch(93.6% 0.018 237.8)
-
Step 200
200
#C5DDED
oklch(88.5% 0.034 237)
-
Step 300
300
#9BC7E4
oklch(80.8% 0.062 237.4)
-
Step 400
400
#60AAD7
oklch(70.8% 0.099 237.1)
-
Step 500
500 (this color)
#178CC4
oklch(60.7% 0.127 236.9)
-
Step 600
600
#007CB1
oklch(55.6% 0.122 237.2)
-
Step 700
700
#006895
oklch(49% 0.107 237)
-
Step 800
800
#00557B
oklch(42.6% 0.093 237.2)
-
Step 900
900
#004767
oklch(37.7% 0.082 236.6)
-
Step 950
950
#062A3D
oklch(27.1% 0.053 236.9)
#178CC4 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) | #718CC7 | 0.072 |
| Deuteranopia (no green cones) | #5A7DC3 | 0.057 |
| Tritanopia (no blue cones) | #009A9F | 0.080 |
| Achromatopsia (no color) | #848484 | 0.127 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178CC4
#178CC4
oklch(60.7% 0.127 236.9)
- #BA6C29
#BA6C29
oklch(60.7% 0.127 57.1)
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 #178CC4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.021
- Blue NCS #118AB2 ΔE 0.028
- Cool Blue #4984B8 ΔE 0.034
- Steel Blue #4682B4 ΔE 0.037
- Off Blue #5684AE ΔE 0.049
- Dusty Blue #5A86AD ΔE 0.052
- Windows Blue #3778BF ΔE 0.055
- Nice Blue #107AB0 ΔE 0.056
Use #178CC4 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.