#51D5EA
Closest named color: Aqua Blue (#02D8E9). oklch(80.9% 0.117 209.9), rgb(81, 213, 234).
Aa
Black text reads best on this color (12.05:1).
About this color
#51D5EA is a light, moderately saturated teal or cyan. In OKLCH its lightness is 81%, its chroma 0.117 and its hue 210°. Its hue sits on the cool side of the wheel. The nearest named color is Aqua Blue (#02D8E9), ΔE 0.024 away. Black text reads best on it, at 12.05:1.
| Hue family | Teals and cyans |
| Lightness | light (81%) |
| Chroma | moderately saturated (0.117) |
| Temperature | cool |
| Nearest name | Aqua Blue (#02D8E9) |
| Black text | 12.05:1 |
| White text | 1.74:1 |
Values
| HEX | #51D5EA |
| RGB | rgb(81, 213, 234) |
| HSL | hsl(188, 78%, 62%) |
| OKLCH | oklch(80.9% 0.117 209.9) |
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 #51D5EA | 1.74:1 | Fails | Lc -35.2 | Non-text elements, placeholder text |
| Black text on #51D5EA | 12.05:1 | AAA | Lc 72.5 | Content text, not long reading |
| #51D5EA text on white | 1.74:1 | Fails | Lc 31.4 | Non-text elements, placeholder text |
| #51D5EA text on black | 12.05:1 | AAA | Lc -71.4 | 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
#EAF9FB
oklch(97.2% 0.016 206.4)
-
Step 100
100
#D1F1F6
oklch(93.7% 0.034 208)
-
Step 200
200
#A7E6F1
oklch(88.6% 0.065 209.5)
-
Step 300
300 (this color)
#51D5EA
oklch(80.9% 0.117 209.9)
-
Step 400
400
#00B5CA
oklch(70.8% 0.122 209.4)
-
Step 500
500
#009BAE
oklch(63.2% 0.109 210)
-
Step 600
600
#008292
oklch(55.6% 0.096 209.8)
-
Step 700
700
#006D7B
oklch(49% 0.085 210.2)
-
Step 800
800
#005A65
oklch(42.8% 0.074 209.1)
-
Step 900
900
#004B55
oklch(37.8% 0.065 210)
-
Step 950
950
#002C33
oklch(26.9% 0.047 211.1)
#51D5EA 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) | #C3CEEB | 0.110 |
| Deuteranopia (no green cones) | #ADBDEA | 0.101 |
| Tritanopia (no blue cones) | #00DFDB | 0.046 |
| Achromatopsia (no color) | #C4C4C4 | 0.117 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #51D5EA
#51D5EA
oklch(80.9% 0.117 209.9)
- #FFA697
#FFA697
oklch(81% 0.108 30.1)
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 #51D5EA, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Aqua Blue #02D8E9 ΔE 0.024
- Vivid Sky Blue #4CC9F0 ΔE 0.038
- Medium Turquoise #48D1CC ΔE 0.043
- Sky Blue #87CEEB ΔE 0.044
- Dark Turquoise #00CED1 ΔE 0.049
- Bright Sky Blue #02CCFE ΔE 0.050
- Lightblue #7BC8F6 ΔE 0.053
- Light Sky Blue #87CEFA ΔE 0.055
Use #51D5EA 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.