#178CDA
Closest named color: Water Blue (#0E87CC). oklch(61.9% 0.151 245.5), rgb(23, 140, 218).
Aa
Black text reads best on this color (5.80:1).
About this color
#178CDA is a medium-dark, vivid blue. In OKLCH its lightness is 62%, its chroma 0.151 and its hue 246°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.024 away. Black text reads best on it, at 5.80:1.
| Hue family | Blues |
| Lightness | medium-dark (62%) |
| Chroma | vivid (0.151) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.80:1 |
| White text | 3.62:1 |
Values
| HEX | #178CDA |
| RGB | rgb(23, 140, 218) |
| HSL | hsl(204, 81%, 47%) |
| OKLCH | oklch(61.9% 0.151 245.5) |
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 #178CDA | 3.62:1 | AA large text | Lc -68.7 | Content text, not long reading |
| Black text on #178CDA | 5.80:1 | AA | Lc 40.8 | Non-text elements, placeholder text |
| #178CDA text on white | 3.62:1 | AA large text | Lc 63.2 | Content text, not long reading |
| #178CDA text on black | 5.80:1 | AA | Lc -38.4 | 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
#F0F6FC
oklch(97% 0.01 247.9)
-
Step 100
100
#DFECF8
oklch(93.7% 0.021 245.9)
-
Step 200
200
#C4DDF3
oklch(88.6% 0.04 244.8)
-
Step 300
300
#99C6EE
oklch(80.9% 0.074 245.7)
-
Step 400
400
#5CA7E5
oklch(70.6% 0.118 245.5)
-
Step 500
500 (this color)
#178CDA
oklch(61.9% 0.151 245.5)
-
Step 600
600
#0079C0
oklch(55.7% 0.141 245.3)
-
Step 700
700
#0065A2
oklch(49% 0.125 245.5)
-
Step 800
800
#005386
oklch(42.8% 0.108 245.3)
-
Step 900
900
#004571
oklch(37.8% 0.096 245.5)
-
Step 950
950
#052943
oklch(27.1% 0.062 245.1)
#178CDA 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) | #668FDD | 0.059 |
| Deuteranopia (no green cones) | #4A7FD9 | 0.042 |
| Tritanopia (no blue cones) | #009FA9 | 0.105 |
| Achromatopsia (no color) | #868686 | 0.151 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178CDA
#178CDA
oklch(61.9% 0.151 245.5)
- #BD7200
#BD7200
oklch(62% 0.138 65.9)
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 #178CDA, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.024
- Dark Sky Blue #448EE4 ΔE 0.031
- Chefchaouen Blue #4895EF ΔE 0.050
- Cool Blue #4984B8 ΔE 0.055
- Dodger Blue #1E90FF ΔE 0.056
- Steel Blue #4682B4 ΔE 0.060
- Windows Blue #3778BF ΔE 0.061
- Blue NCS #118AB2 ΔE 0.062
Use #178CDA 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.