#178FC3
Closest named color: Blue NCS (#118AB2). oklch(61.4% 0.124 234.4), rgb(23, 143, 195).
Aa
Black text reads best on this color (5.75:1).
About this color
#178FC3 is a medium-dark, moderately saturated blue. In OKLCH its lightness is 61%, its chroma 0.124 and its hue 234°. Its hue sits on the cool side of the wheel. The nearest named color is Blue NCS (#118AB2), ΔE 0.028 away. Black text reads best on it, at 5.75:1.
| Hue family | Blues |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.124) |
| Temperature | cool |
| Nearest name | Blue NCS (#118AB2) |
| Black text | 5.75:1 |
| White text | 3.64:1 |
Values
| HEX | #178FC3 |
| RGB | rgb(23, 143, 195) |
| HSL | hsl(198, 79%, 43%) |
| OKLCH | oklch(61.4% 0.124 234.4) |
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 #178FC3 | 3.64:1 | AA large text | Lc -69.1 | Content text, not long reading |
| Black text on #178FC3 | 5.75:1 | AA | Lc 40.5 | Non-text elements, placeholder text |
| #178FC3 text on white | 3.64:1 | AA large text | Lc 63.6 | Content text, not long reading |
| #178FC3 text on black | 5.75:1 | AA | Lc -38.1 | 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
#C5DDEC
oklch(88.4% 0.033 235.2)
-
Step 300
300
#9BC8E2
oklch(81% 0.06 233.8)
-
Step 400
400
#5FAAD4
oklch(70.6% 0.097 234.9)
-
Step 500
500 (this color)
#178FC3
oklch(61.4% 0.124 234.4)
-
Step 600
600
#007DAD
oklch(55.6% 0.117 234.3)
-
Step 700
700
#006992
oklch(49.1% 0.103 234.3)
-
Step 800
800
#005678
oklch(42.7% 0.089 233.9)
-
Step 900
900
#004865
oklch(37.8% 0.079 233.7)
-
Step 950
950
#062A3C
oklch(27% 0.052 235.4)
#178FC3 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) | #758EC5 | 0.075 |
| Deuteranopia (no green cones) | #5F7FC2 | 0.062 |
| Tritanopia (no blue cones) | #009DA1 | 0.076 |
| Achromatopsia (no color) | #868686 | 0.124 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #178FC3
#178FC3
oklch(61.4% 0.124 234.4)
- #BC6E33
#BC6E33
oklch(61.4% 0.123 54.8)
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 #178FC3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue NCS #118AB2 ΔE 0.028
- Water Blue #0E87CC ΔE 0.030
- Cool Blue #4984B8 ΔE 0.038
- Steel Blue #4682B4 ΔE 0.042
- Off Blue #5684AE ΔE 0.050
- Dusty Blue #5A86AD ΔE 0.052
- Faded Blue #658CBB ΔE 0.055
- Teal Blue #01889F ΔE 0.057
Use #178FC3 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.