#42B7F3
Closest named color: Deep Sky Blue (#00BFFF). oklch(74% 0.134 235.4), rgb(66, 183, 243).
Aa
Black text reads best on this color (9.29:1).
About this color
#42B7F3 is a medium-light, moderately saturated blue. In OKLCH its lightness is 74%, its chroma 0.134 and its hue 235°. Its hue sits on the cool side of the wheel. The nearest named color is Deep Sky Blue (#00BFFF), ΔE 0.027 away. Black text reads best on it, at 9.29:1.
| Hue family | Blues |
| Lightness | medium-light (74%) |
| Chroma | moderately saturated (0.134) |
| Temperature | cool |
| Nearest name | Deep Sky Blue (#00BFFF) |
| Black text | 9.29:1 |
| White text | 2.25:1 |
Values
| HEX | #42B7F3 |
| RGB | rgb(66, 183, 243) |
| HSL | hsl(200, 88%, 61%) |
| OKLCH | oklch(74% 0.134 235.4) |
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 #42B7F3 | 2.25:1 | Fails | Lc -49.0 | Large or bold text, headings |
| Black text on #42B7F3 | 9.29:1 | AAA | Lc 59.8 | Large or bold text, headings |
| #42B7F3 text on white | 2.25:1 | Fails | Lc 44.2 | Non-text elements, placeholder text |
| #42B7F3 text on black | 9.29:1 | AAA | Lc -58.0 | 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
#EFF7FC
oklch(97.2% 0.011 234.8)
-
Step 100
100
#DBEDF8
oklch(93.6% 0.024 234.4)
-
Step 200
200
#BDDFF4
oklch(88.6% 0.046 235.2)
-
Step 300
300
#8ACAEF
oklch(80.9% 0.084 234.6)
-
Step 400
400 (this color)
#42B7F3
oklch(74% 0.134 235.4)
-
Step 500
500
#0094CF
oklch(63% 0.135 235.8)
-
Step 600
600
#007DAF
oklch(55.7% 0.119 235.4)
-
Step 700
700
#006993
oklch(49.2% 0.104 234.9)
-
Step 800
800
#00567A
oklch(42.8% 0.091 235.4)
-
Step 900
900
#004766
oklch(37.6% 0.081 235.8)
-
Step 950
950
#002A3E
oklch(26.9% 0.057 235.2)
#42B7F3 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) | #9AB6F6 | 0.081 |
| Deuteranopia (no green cones) | #82A5F2 | 0.067 |
| Tritanopia (no blue cones) | #00C7CB | 0.087 |
| Achromatopsia (no color) | #ACACAC | 0.134 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #42B7F3
#42B7F3
oklch(74% 0.134 235.4)
- #EB9251
#EB9251
oklch(74% 0.134 55)
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 #42B7F3, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Deep Sky Blue #00BFFF ΔE 0.027
- Vivid Sky Blue #4CC9F0 ΔE 0.053
- Bright Sky Blue #02CCFE ΔE 0.055
- Carolina Blue #8AB8FE ΔE 0.066
- Lightblue #7BC8F6 ΔE 0.069
- Turquoise Blue #06B1C4 ΔE 0.075
- Sky #82CAFC ΔE 0.078
- Light Sky Blue #87CEFA ΔE 0.090
Use #42B7F3 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.