#178AD5
Closest named color: Water Blue (#0E87CC). oklch(61.2% 0.147 244.9), rgb(23, 138, 213).
Aa
Black text reads best on this color (5.63:1).
About this color
#178AD5 is a medium-dark, vivid blue. In OKLCH its lightness is 61%, its chroma 0.147 and its hue 245°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.016 away. Black text reads best on it, at 5.63:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | vivid (0.147) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.63:1 |
| White text | 3.72:1 |
Values
| HEX | #178AD5 |
| RGB | rgb(23, 138, 213) |
| HSL | hsl(204, 81%, 46%) |
| OKLCH | oklch(61.2% 0.147 244.9) |
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 #178AD5 | 3.72:1 | AA large text | Lc -69.8 | Content text, not long reading |
| Black text on #178AD5 | 5.63:1 | AA | Lc 39.8 | Non-text elements, placeholder text |
| #178AD5 text on white | 3.72:1 | AA large text | Lc 64.3 | Content text, not long reading |
| #178AD5 text on black | 5.63:1 | AA | Lc -37.4 | 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
#DFECF7
oklch(93.7% 0.02 243.4)
-
Step 200
200
#C4DDF2
oklch(88.6% 0.039 243.5)
-
Step 300
300
#9AC6EC
oklch(80.8% 0.071 244.9)
-
Step 400
400
#5EA8E3
oklch(70.8% 0.114 244.5)
-
Step 500
500 (this color)
#178AD5
oklch(61.2% 0.147 244.9)
-
Step 600
600
#0079BF
oklch(55.7% 0.14 245)
-
Step 700
700
#0065A1
oklch(49% 0.124 245.1)
-
Step 800
800
#005385
oklch(42.7% 0.107 244.8)
-
Step 900
900
#004570
oklch(37.7% 0.095 244.9)
-
Step 950
950
#062942
oklch(27.1% 0.061 244.7)
#178AD5 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) | #668DD8 | 0.060 |
| Deuteranopia (no green cones) | #4B7DD4 | 0.043 |
| Tritanopia (no blue cones) | #009CA5 | 0.102 |
| Achromatopsia (no color) | #848484 | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178AD5
#178AD5
oklch(61.2% 0.147 244.9)
- #BB6F00
#BB6F00
oklch(61.2% 0.138 64.7)
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 #178AD5, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.016
- Dark Sky Blue #448EE4 ΔE 0.037
- Cool Blue #4984B8 ΔE 0.049
- Steel Blue #4682B4 ΔE 0.053
- Windows Blue #3778BF ΔE 0.054
- Blue NCS #118AB2 ΔE 0.055
- Chefchaouen Blue #4895EF ΔE 0.058
- Dodger Blue #1E90FF ΔE 0.064
Use #178AD5 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.