#21D5EB
Closest named color: Aqua Blue (#02D8E9). oklch(80.1% 0.133 208.4), rgb(33, 213, 235).
Aa
Black text reads best on this color (11.78:1).
About this color
#21D5EB is a light, moderately saturated teal or cyan. In OKLCH its lightness is 80%, its chroma 0.133 and its hue 208°. Its hue sits on the cool side of the wheel. The nearest named color is Aqua Blue (#02D8E9), ΔE 0.010 away. Black text reads best on it, at 11.78:1.
| Hue family | Teals and cyans |
| Lightness | light (80%) |
| Chroma | moderately saturated (0.133) |
| Temperature | cool |
| Nearest name | Aqua Blue (#02D8E9) |
| Black text | 11.78:1 |
| White text | 1.78:1 |
Values
| HEX | #21D5EB |
| RGB | rgb(33, 213, 235) |
| HSL | hsl(187, 83%, 53%) |
| OKLCH | oklch(80.1% 0.133 208.4) |
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 #21D5EB | 1.78:1 | Fails | Lc -36.3 | Non-text elements, placeholder text |
| Black text on #21D5EB | 11.78:1 | AAA | Lc 71.5 | Content text, not long reading |
| #21D5EB text on white | 1.78:1 | Fails | Lc 32.3 | Non-text elements, placeholder text |
| #21D5EB text on black | 11.78:1 | AAA | Lc -70.4 | Content text, not long reading |
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 300.
-
Step 50
50
#E9F9FC
oklch(97.1% 0.017 210.2)
-
Step 100
100
#CDF2F8
oklch(93.7% 0.039 208.4)
-
Step 200
200
#9EE7F3
oklch(88.4% 0.074 208.8)
-
Step 300
300 (this color)
#21D5EB
oklch(80.1% 0.133 208.4)
-
Step 400
400
#00B5C8
oklch(70.7% 0.122 208)
-
Step 500
500
#009BAC
oklch(63.1% 0.109 208.4)
-
Step 600
600
#008291
oklch(55.5% 0.096 208.9)
-
Step 700
700
#006E7A
oklch(49.2% 0.085 207.9)
-
Step 800
800
#005A64
oklch(42.8% 0.073 207.9)
-
Step 900
900
#004B54
oklch(37.8% 0.065 208.5)
-
Step 950
950
#002C32
oklch(26.8% 0.046 208.8)
#21D5EB 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) | #C1CDEC | 0.127 |
| Deuteranopia (no green cones) | #A7BAEB | 0.116 |
| Tritanopia (no blue cones) | #00DFDC | 0.041 |
| Achromatopsia (no color) | #C2C2C2 | 0.134 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21D5EB
#21D5EB
oklch(80.1% 0.133 208.4)
- #FFA194
#FFA194
oklch(80% 0.114 28.4)
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 #21D5EB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Aqua Blue #02D8E9 ΔE 0.010
- Vivid Sky Blue #4CC9F0 ΔE 0.038
- Dark Turquoise #00CED1 ΔE 0.040
- Medium Turquoise #48D1CC ΔE 0.043
- Bright Sky Blue #02CCFE ΔE 0.043
- Turquoise #40E0D0 ΔE 0.058
- Sky Blue #87CEEB ΔE 0.062
- Lightblue #7BC8F6 ΔE 0.065
Use #21D5EB 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.