#42BCDF
Closest named color: Vivid Sky Blue (#4CC9F0). oklch(74.2% 0.116 220.9), rgb(66, 188, 223).
Aa
Black text reads best on this color (9.49:1).
About this color
#42BCDF is a medium-light, moderately saturated teal or cyan. In OKLCH its lightness is 74%, its chroma 0.116 and its hue 221°. Its hue sits on the cool side of the wheel. The nearest named color is Vivid Sky Blue (#4CC9F0), ΔE 0.040 away. Black text reads best on it, at 9.49:1.
| Hue family | Teals and cyans |
| Lightness | medium-light (74%) |
| Chroma | moderately saturated (0.116) |
| Temperature | cool |
| Nearest name | Vivid Sky Blue (#4CC9F0) |
| Black text | 9.49:1 |
| White text | 2.21:1 |
Values
| HEX | #42BCDF |
| RGB | rgb(66, 188, 223) |
| HSL | hsl(193, 71%, 57%) |
| OKLCH | oklch(74.2% 0.116 220.9) |
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 #42BCDF | 2.21:1 | Fails | Lc -48.0 | Large or bold text, headings |
| Black text on #42BCDF | 9.49:1 | AAA | Lc 60.7 | Content text, not long reading |
| #42BCDF text on white | 2.21:1 | Fails | Lc 43.2 | Non-text elements, placeholder text |
| #42BCDF text on black | 9.49:1 | AAA | Lc -58.9 | Large or bold text, headings |
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 400.
-
Step 50
50
#EFF7FA
oklch(97.1% 0.009 222.1)
-
Step 100
100
#DBEDF4
oklch(93.5% 0.021 223)
-
Step 200
200
#BDE0EC
oklch(88.5% 0.04 220.6)
-
Step 300
300
#8BCCE2
oklch(80.9% 0.073 221.2)
-
Step 400
400 (this color)
#42BCDF
oklch(74.2% 0.116 220.9)
-
Step 500
500
#0099BA
oklch(63.2% 0.115 220.3)
-
Step 600
600
#00809D
oklch(55.6% 0.102 221.1)
-
Step 700
700
#006C84
oklch(49.2% 0.09 220.2)
-
Step 800
800
#00586D
oklch(42.6% 0.078 221.3)
-
Step 900
900
#00495B
oklch(37.6% 0.069 221.4)
-
Step 950
950
#002C37
oklch(27.1% 0.049 219.4)
#42BCDF 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) | #A7B7E1 | 0.096 |
| Deuteranopia (no green cones) | #91A7DF | 0.086 |
| Tritanopia (no blue cones) | #00C7C7 | 0.057 |
| Achromatopsia (no color) | #AEAEAE | 0.117 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #42BCDF
#42BCDF
oklch(74.2% 0.116 220.9)
- #EA9271
#EA9271
oklch(74.3% 0.117 41.2)
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 #42BCDF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Vivid Sky Blue #4CC9F0 ΔE 0.040
- Deep Sky Blue #00BFFF ΔE 0.047
- Bright Sky Blue #02CCFE ΔE 0.053
- Turquoise Blue #06B1C4 ΔE 0.053
- Dark Turquoise #00CED1 ΔE 0.062
- Lightblue #7BC8F6 ΔE 0.066
- Medium Turquoise #48D1CC ΔE 0.074
- Aqua Blue #02D8E9 ΔE 0.075
Use #42BCDF 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.