#63B4DF
Closest named color: Vivid Sky Blue (#4CC9F0). oklch(73.5% 0.101 233.6), rgb(99, 180, 223).
Aa
Black text reads best on this color (9.12:1).
About this color
#63B4DF is a medium-light, moderately saturated blue. In OKLCH its lightness is 74%, its chroma 0.101 and its hue 234°. Its hue sits on the cool side of the wheel. The nearest named color is Vivid Sky Blue (#4CC9F0), ΔE 0.056 away. Black text reads best on it, at 9.12:1.
| Hue family | Blues |
| Lightness | medium-light (74%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Vivid Sky Blue (#4CC9F0) |
| Black text | 9.12:1 |
| White text | 2.30:1 |
Values
| HEX | #63B4DF |
| RGB | rgb(99, 180, 223) |
| HSL | hsl(201, 66%, 63%) |
| OKLCH | oklch(73.5% 0.101 233.6) |
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 #63B4DF | 2.30:1 | Fails | Lc -50.1 | Large or bold text, headings |
| Black text on #63B4DF | 9.12:1 | AAA | Lc 58.8 | Large or bold text, headings |
| #63B4DF text on white | 2.30:1 | Fails | Lc 45.2 | Large or bold text, headings |
| #63B4DF text on black | 9.12:1 | AAA | Lc -56.9 | 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
#F0F7FA
oklch(97.2% 0.008 225.1)
-
Step 100
100
#DFECF4
oklch(93.6% 0.018 234.5)
-
Step 200
200
#C3DEED
oklch(88.5% 0.035 232.1)
-
Step 300
300
#99C8E3
oklch(80.9% 0.062 233.7)
-
Step 400
400 (this color)
#63B4DF
oklch(73.5% 0.101 233.6)
-
Step 500
500
#0D95CB
oklch(63.1% 0.129 233.7)
-
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
#004864
oklch(37.8% 0.078 232.8)
-
Step 950
950
#032A3C
oklch(26.9% 0.053 233.9)
#63B4DF 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) | #9FB2E1 | 0.065 |
| Deuteranopia (no green cones) | #8EA5DE | 0.057 |
| Tritanopia (no blue cones) | #00BFC2 | 0.075 |
| Achromatopsia (no color) | #ABABAB | 0.101 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #63B4DF
#63B4DF
oklch(73.5% 0.101 233.6)
- #DB986B
#DB986B
oklch(73.5% 0.101 54.4)
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 #63B4DF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Vivid Sky Blue #4CC9F0 ΔE 0.056
- Deep Sky Blue #00BFFF ΔE 0.056
- Carolina Blue #8AB8FE ΔE 0.063
- Turquoise Blue #06B1C4 ΔE 0.065
- Lightblue #7BC8F6 ΔE 0.065
- Greyblue #77A1B5 ΔE 0.068
- Light Grey Blue #9DBCD4 ΔE 0.070
- Light Cornflower Blue #98C1D9 ΔE 0.071
Use #63B4DF 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.