#178CBB
Closest named color: Blue NCS (#118AB2). oklch(60.2% 0.118 232.2), rgb(23, 140, 187).
Aa
Black text reads best on this color (5.50:1).
About this color
#178CBB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 60%, its chroma 0.118 and its hue 232°. Its hue sits on the cool side of the wheel. The nearest named color is Blue NCS (#118AB2), ΔE 0.014 away. Black text reads best on it, at 5.50:1.
| Hue family | Blues |
| Lightness | medium-dark (60%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Blue NCS (#118AB2) |
| Black text | 5.50:1 |
| White text | 3.81:1 |
Values
| HEX | #178CBB |
| RGB | rgb(23, 140, 187) |
| HSL | hsl(197, 78%, 41%) |
| OKLCH | oklch(60.2% 0.118 232.2) |
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 #178CBB | 3.81:1 | AA large text | Lc -70.7 | Content text, not long reading |
| Black text on #178CBB | 5.50:1 | AA | Lc 38.9 | Non-text elements, placeholder text |
| #178CBB text on white | 3.81:1 | AA large text | Lc 65.2 | Content text, not long reading |
| #178CBB text on black | 5.50:1 | AA | Lc -36.5 | 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
#F1F6FA
oklch(97.1% 0.008 241.7)
-
Step 100
100
#DFECF3
oklch(93.5% 0.017 230.9)
-
Step 200
200
#C5DDEB
oklch(88.4% 0.032 233.3)
-
Step 300
300
#9CC8E0
oklch(81% 0.057 232.2)
-
Step 400
400
#61ABD0
oklch(70.8% 0.092 231.8)
-
Step 500
500 (this color)
#178CBB
oklch(60.2% 0.118 232.2)
-
Step 600
600
#007EAA
oklch(55.7% 0.113 231.8)
-
Step 700
700
#006A90
oklch(49.2% 0.1 232)
-
Step 800
800
#005676
oklch(42.6% 0.087 232.3)
-
Step 900
900
#014863
oklch(37.7% 0.076 232)
-
Step 950
950
#072A3A
oklch(26.9% 0.049 232.7)
#178CBB 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) | #748BBD | 0.076 |
| Deuteranopia (no green cones) | #5F7CBA | 0.064 |
| Tritanopia (no blue cones) | #00999C | 0.070 |
| Achromatopsia (no color) | #838383 | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178CBB
#178CBB
oklch(60.2% 0.118 232.2)
- #B76B38
#B76B38
oklch(60.3% 0.117 52.4)
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 #178CBB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue NCS #118AB2 ΔE 0.014
- Water Blue #0E87CC ΔE 0.033
- Cool Blue #4984B8 ΔE 0.033
- Steel Blue #4682B4 ΔE 0.035
- Teal Blue #01889F ΔE 0.044
- Off Blue #5684AE ΔE 0.044
- Dusty Blue #5A86AD ΔE 0.047
- Nice Blue #107AB0 ΔE 0.053
Use #178CBB 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.