#21D1DF
Closest named color: Aqua Blue (#02D8E9). oklch(78.6% 0.13 203.7), rgb(33, 209, 223).
Aa
Black text reads best on this color (11.25:1).
About this color
#21D1DF is a light, moderately saturated teal or cyan. In OKLCH its lightness is 79%, its chroma 0.130 and its hue 204°. Its hue sits on the cool side of the wheel. The nearest named color is Aqua Blue (#02D8E9), ΔE 0.020 away. Black text reads best on it, at 11.25:1.
| Hue family | Teals and cyans |
| Lightness | light (79%) |
| Chroma | moderately saturated (0.130) |
| Temperature | cool |
| Nearest name | Aqua Blue (#02D8E9) |
| Black text | 11.25:1 |
| White text | 1.86:1 |
Values
| HEX | #21D1DF |
| RGB | rgb(33, 209, 223) |
| HSL | hsl(184, 75%, 50%) |
| OKLCH | oklch(78.6% 0.13 203.7) |
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 #21D1DF | 1.86:1 | Fails | Lc -38.9 | Non-text elements, placeholder text |
| Black text on #21D1DF | 11.25:1 | AAA | Lc 69.2 | Content text, not long reading |
| #21D1DF text on white | 1.86:1 | Fails | Lc 34.7 | Non-text elements, placeholder text |
| #21D1DF text on black | 11.25:1 | AAA | Lc -67.8 | 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
#E9F9FB
oklch(97.1% 0.017 205.8)
-
Step 100
100
#CEF2F5
oklch(93.6% 0.038 202.7)
-
Step 200
200
#A0E8EF
oklch(88.6% 0.072 203.6)
-
Step 300
300 (this color)
#21D1DF
oklch(78.6% 0.13 203.7)
-
Step 400
400
#00B6C3
oklch(70.8% 0.121 203.9)
-
Step 500
500
#009CA7
oklch(63.1% 0.108 203.6)
-
Step 600
600
#00838C
oklch(55.6% 0.095 203.3)
-
Step 700
700
#006E76
oklch(49.1% 0.084 203.6)
-
Step 800
800
#005A61
oklch(42.6% 0.073 204)
-
Step 900
900
#004B51
oklch(37.6% 0.064 204)
-
Step 950
950
#002D31
oklch(27.1% 0.046 204.1)
#21D1DF 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) | #BFC8E0 | 0.128 |
| Deuteranopia (no green cones) | #A7B6E0 | 0.119 |
| Tritanopia (no blue cones) | #00DAD5 | 0.033 |
| Achromatopsia (no color) | #BEBEBE | 0.130 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21D1DF
#21D1DF
oklch(78.6% 0.13 203.7)
- #FF9993
#FF9993
oklch(78.7% 0.123 23.8)
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 #21D1DF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Aqua Blue #02D8E9 ΔE 0.020
- Dark Turquoise #00CED1 ΔE 0.022
- Medium Turquoise #48D1CC ΔE 0.029
- Vivid Sky Blue #4CC9F0 ΔE 0.042
- Bright Sky Blue #02CCFE ΔE 0.051
- Turquoise #40E0D0 ΔE 0.055
- Sky Blue #87CEEB ΔE 0.068
- Seafoam Blue #78D1B6 ΔE 0.070
Use #21D1DF 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.