#178BBC
Closest named color: Blue NCS (#118AB2). oklch(60% 0.119 233.6), rgb(23, 139, 188).
Aa
Black text reads best on this color (5.45:1).
About this color
#178BBC is a medium-dark, moderately saturated blue. In OKLCH its lightness is 60%, its chroma 0.119 and its hue 234°. Its hue sits on the cool side of the wheel. The nearest named color is Blue NCS (#118AB2), ΔE 0.016 away. Black text reads best on it, at 5.45:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | moderately saturated (0.119) |
| Temperature | cool |
| Nearest name | Blue NCS (#118AB2) |
| Black text | 5.45:1 |
| White text | 3.84:1 |
Values
| HEX | #178BBC |
| RGB | rgb(23, 139, 188) |
| HSL | hsl(198, 78%, 41%) |
| OKLCH | oklch(60% 0.119 233.6) |
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 #178BBC | 3.84:1 | AA large text | Lc -71.0 | Content text, not long reading |
| Black text on #178BBC | 5.45:1 | AA | Lc 38.6 | Non-text elements, placeholder text |
| #178BBC text on white | 3.84:1 | AA large text | Lc 65.5 | Content text, not long reading |
| #178BBC text on black | 5.45:1 | AA | Lc -36.2 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#DFECF4
oklch(93.6% 0.018 234.5)
-
Step 200
200
#C5DDEC
oklch(88.4% 0.033 235.2)
-
Step 300
300
#9CC8E1
oklch(81% 0.058 233.3)
-
Step 400
400
#61AAD2
oklch(70.6% 0.094 234.2)
-
Step 500
500 (this color)
#178BBC
oklch(60% 0.119 233.6)
-
Step 600
600
#007DAC
oklch(55.5% 0.116 233.8)
-
Step 700
700
#006991
oklch(49% 0.102 233.6)
-
Step 800
800
#005678
oklch(42.7% 0.089 233.9)
-
Step 900
900
#014864
oklch(37.8% 0.077 232.9)
-
Step 950
950
#072A3B
oklch(27% 0.05 234.4)
#178BBC 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) | #738ABE | 0.075 |
| Deuteranopia (no green cones) | #5E7CBB | 0.061 |
| Tritanopia (no blue cones) | #00989C | 0.072 |
| Achromatopsia (no color) | #828282 | 0.120 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178BBC
#178BBC
oklch(60% 0.119 233.6)
- #B76A34
#B76A34
oklch(60.1% 0.12 53.2)
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 #178BBC, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue NCS #118AB2 ΔE 0.016
- Water Blue #0E87CC ΔE 0.030
- Cool Blue #4984B8 ΔE 0.032
- Steel Blue #4682B4 ΔE 0.033
- Off Blue #5684AE ΔE 0.044
- Teal Blue #01889F ΔE 0.046
- Dusty Blue #5A86AD ΔE 0.048
- Nice Blue #107AB0 ΔE 0.050
Use #178BBC 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.