#178FC4
Closest named color: Water Blue (#0E87CC). oklch(61.4% 0.125 234.9), rgb(23, 143, 196).
Aa
Black text reads best on this color (5.76:1).
About this color
#178FC4 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.125 and its hue 235°. Its hue sits on the cool side of the wheel. The nearest named color is Water Blue (#0E87CC), ΔE 0.029 away. Black text reads best on it, at 5.76:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Water Blue (#0E87CC) |
| Black text | 5.76:1 |
| White text | 3.64:1 |
Values
| HEX | #178FC4 |
| RGB | rgb(23, 143, 196) |
| HSL | hsl(198, 79%, 43%) |
| OKLCH | oklch(61.4% 0.125 234.9) |
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 #178FC4 | 3.64:1 | AA large text | Lc -69.0 | Content text, not long reading |
| Black text on #178FC4 | 5.76:1 | AA | Lc 40.6 | Non-text elements, placeholder text |
| #178FC4 text on white | 3.64:1 | AA large text | Lc 63.5 | Content text, not long reading |
| #178FC4 text on black | 5.76:1 | AA | Lc -38.2 | 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
#F0F6FA
oklch(97% 0.008 236.6)
-
Step 100
100
#DFECF4
oklch(93.6% 0.018 234.5)
-
Step 200
200
#C5DDED
oklch(88.5% 0.034 237)
-
Step 300
300
#9BC8E3
oklch(81% 0.061 234.9)
-
Step 400
400
#5FAAD5
oklch(70.6% 0.098 235.6)
-
Step 500
500 (this color)
#178FC4
oklch(61.4% 0.125 234.9)
-
Step 600
600
#007DAE
oklch(55.7% 0.118 234.9)
-
Step 700
700
#006993
oklch(49.2% 0.104 234.9)
-
Step 800
800
#005679
oklch(42.8% 0.09 234.7)
-
Step 900
900
#004766
oklch(37.6% 0.081 235.8)
-
Step 950
950
#062A3C
oklch(27% 0.052 235.4)
#178FC4 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) | #758EC6 | 0.075 |
| Deuteranopia (no green cones) | #5F7FC3 | 0.062 |
| Tritanopia (no blue cones) | #009DA1 | 0.077 |
| Achromatopsia (no color) | #868686 | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178FC4
#178FC4
oklch(61.4% 0.125 234.9)
- #BD6E31
#BD6E31
oklch(61.5% 0.125 55.1)
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 #178FC4, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Water Blue #0E87CC ΔE 0.029
- Blue NCS #118AB2 ΔE 0.029
- Cool Blue #4984B8 ΔE 0.038
- Steel Blue #4682B4 ΔE 0.042
- Off Blue #5684AE ΔE 0.051
- Dusty Blue #5A86AD ΔE 0.053
- Faded Blue #658CBB ΔE 0.055
- Dark Sky Blue #448EE4 ΔE 0.058
Use #178FC4 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.