#178CDB
Closest named color: Water Blue (#0E87CC). oklch(62% 0.152 245.8), rgb(23, 140, 219).
Aa
Black text reads best on this color (5.81:1).
About this color
#178CDB is a medium-dark, vivid blue. In OKLCH its lightness is 62%, its chroma 0.152 and its hue 246°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.025 away. Black text reads best on it, at 5.81:1.
| Hue family | Blues |
| Lightness | medium-dark (62%) |
| Chroma | vivid (0.152) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.81:1 |
| White text | 3.61:1 |
Values
| HEX | #178CDB |
| RGB | rgb(23, 140, 219) |
| HSL | hsl(204, 81%, 47%) |
| OKLCH | oklch(62% 0.152 245.8) |
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 #178CDB | 3.61:1 | AA large text | Lc -68.6 | Content text, not long reading |
| Black text on #178CDB | 5.81:1 | AA | Lc 40.9 | Non-text elements, placeholder text |
| #178CDB text on white | 3.61:1 | AA large text | Lc 63.2 | Content text, not long reading |
| #178CDB text on black | 5.81:1 | AA | Lc -38.5 | 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
#5CA7E6
oklch(70.6% 0.119 245.9)
-
Step 500
500 (this color)
#178CDB
oklch(62% 0.152 245.8)
-
Step 600
600
#0078C1
oklch(55.5% 0.143 246.2)
-
Step 700
700
#0065A3
oklch(49.1% 0.126 245.9)
-
Step 800
800
#005387
oklch(42.8% 0.11 245.8)
-
Step 900
900
#004571
oklch(37.8% 0.096 245.5)
-
Step 950
950
#052943
oklch(27.1% 0.062 245.1)
#178CDB 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) | #6690DE | 0.060 |
| Deuteranopia (no green cones) | #497FDA | 0.041 |
| Tritanopia (no blue cones) | #009FA9 | 0.106 |
| Achromatopsia (no color) | #878787 | 0.152 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178CDB
#178CDB
oklch(62% 0.152 245.8)
- #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 #178CDB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.025
- Dark Sky Blue #448EE4 ΔE 0.030
- Chefchaouen Blue #4895EF ΔE 0.049
- Dodger Blue #1E90FF ΔE 0.054
- Cool Blue #4984B8 ΔE 0.056
- Soft Blue #6488EA ΔE 0.061
- Steel Blue #4682B4 ΔE 0.062
- Windows Blue #3778BF ΔE 0.062
Use #178CDB 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.