#21B2EE
Closest named color: Deep Sky Blue (#00BFFF). oklch(71.9% 0.142 232.9), rgb(33, 178, 238).
Aa
Black text reads best on this color (8.66:1).
About this color
#21B2EE is a medium-light, vivid blue. In OKLCH its lightness is 72%, its chroma 0.142 and its hue 233°. Its hue sits on the cool side of the wheel. The nearest named color is Deep Sky Blue (#00BFFF), ΔE 0.038 away. Black text reads best on it, at 8.66:1.
| Hue family | Blues |
| Lightness | medium-light (72%) |
| Chroma | vivid (0.142) |
| Temperature | cool |
| Nearest name | Deep Sky Blue (#00BFFF) |
| Black text | 8.66:1 |
| White text | 2.42:1 |
Values
| HEX | #21B2EE |
| RGB | rgb(33, 178, 238) |
| HSL | hsl(198, 86%, 53%) |
| OKLCH | oklch(71.9% 0.142 232.9) |
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 #21B2EE | 2.42:1 | Fails | Lc -52.1 | Large or bold text, headings |
| Black text on #21B2EE | 8.66:1 | AAA | Lc 56.8 | Large or bold text, headings |
| #21B2EE text on white | 2.42:1 | Fails | Lc 47.2 | Large or bold text, headings |
| #21B2EE text on black | 8.66:1 | AAA | Lc -54.9 | 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
#EEF7FC
oklch(97.1% 0.012 231.7)
-
Step 100
100
#DAEDF8
oklch(93.5% 0.025 233)
-
Step 200
200
#BADFF5
oklch(88.4% 0.049 234.2)
-
Step 300
300
#85CBF1
oklch(81% 0.089 233.1)
-
Step 400
400 (this color)
#21B2EE
oklch(71.9% 0.142 232.9)
-
Step 500
500
#0095CB
oklch(63% 0.131 233.2)
-
Step 600
600
#007DAB
oklch(55.5% 0.115 233.2)
-
Step 700
700
#006990
oklch(49% 0.101 232.9)
-
Step 800
800
#005677
oklch(42.6% 0.088 233.1)
-
Step 900
900
#004864
oklch(37.8% 0.078 232.8)
-
Step 950
950
#002A3D
oklch(26.9% 0.056 233.8)
#21B2EE 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) | #94B0F1 | 0.090 |
| Deuteranopia (no green cones) | #7A9EED | 0.076 |
| Tritanopia (no blue cones) | #00C2C6 | 0.085 |
| Achromatopsia (no color) | #A6A6A6 | 0.142 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21B2EE
#21B2EE
oklch(71.9% 0.142 232.9)
- #E88947
#E88947
oklch(72% 0.141 53.1)
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 #21B2EE, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Deep Sky Blue #00BFFF ΔE 0.038
- Turquoise Blue #06B1C4 ΔE 0.064
- Bright Sky Blue #02CCFE ΔE 0.070
- Vivid Sky Blue #4CC9F0 ΔE 0.070
- Chefchaouen Blue #4895EF ΔE 0.079
- Cornflower Blue #6495ED ΔE 0.083
- Carolina Blue #8AB8FE ΔE 0.086
- Lightblue #7BC8F6 ΔE 0.091
Use #21B2EE 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.