#178DE0
Closest named color: Dark Sky Blue (#448EE4). oklch(62.5% 0.157 246.9), rgb(23, 141, 224).
Aa
Black text reads best on this color (5.92:1).
About this color
#178DE0 is a medium-light, vivid blue. In OKLCH its lightness is 63%, its chroma 0.157 and its hue 247°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Sky Blue (#448EE4), ΔE 0.026 away. Black text reads best on it, at 5.92:1.
| Hue family | Blues |
| Lightness | medium-light (63%) |
| Chroma | vivid (0.157) |
| Temperature | cool |
| Nearest name | Dark Sky Blue (#448EE4) |
| Black text | 5.92:1 |
| White text | 3.54:1 |
Values
| HEX | #178DE0 |
| RGB | rgb(23, 141, 224) |
| HSL | hsl(205, 81%, 48%) |
| OKLCH | oklch(62.5% 0.157 246.9) |
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 #178DE0 | 3.54:1 | AA large text | Lc -67.9 | Content text, not long reading |
| Black text on #178DE0 | 5.92:1 | AA | Lc 41.6 | Non-text elements, placeholder text |
| #178DE0 text on white | 3.54:1 | AA large text | Lc 62.5 | Content text, not long reading |
| #178DE0 text on black | 5.92:1 | AA | Lc -39.2 | 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
#DEECF8
oklch(93.6% 0.022 243.8)
-
Step 200
200
#C3DDF4
oklch(88.6% 0.042 245)
-
Step 300
300
#99C6F0
oklch(80.9% 0.076 247)
-
Step 400
400
#5BA7E9
oklch(70.7% 0.123 246.8)
-
Step 500
500 (this color)
#178DE0
oklch(62.5% 0.157 246.9)
-
Step 600
600
#0078C3
oklch(55.7% 0.146 246.8)
-
Step 700
700
#0064A5
oklch(49% 0.13 247.2)
-
Step 800
800
#005288
oklch(42.7% 0.112 246.9)
-
Step 900
900
#004472
oklch(37.6% 0.099 246.8)
-
Step 950
950
#052844
oklch(26.9% 0.065 247.5)
#178DE0 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) | #6591E3 | 0.058 |
| Deuteranopia (no green cones) | #4780DE | 0.039 |
| Tritanopia (no blue cones) | #00A1AC | 0.110 |
| Achromatopsia (no color) | #888888 | 0.157 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178DE0
#178DE0
oklch(62.5% 0.157 246.9)
- #BE7400
#BE7400
oklch(62.5% 0.138 66.8)
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 #178DE0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Sky Blue #448EE4 ΔE 0.026
- Water Blue #0E87CC ΔE 0.033
- Chefchaouen Blue #4895EF ΔE 0.043
- Dodger Blue #1E90FF ΔE 0.047
- Soft Blue #6488EA ΔE 0.058
- Cool Blue #4984B8 ΔE 0.063
- Cornflower Blue #6495ED ΔE 0.064
- Windows Blue #3778BF ΔE 0.068
Use #178DE0 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.