#51BFDB
Closest named color: Vivid Sky Blue (#4CC9F0). oklch(75.2% 0.107 217.5), rgb(81, 191, 219).
Aa
Black text reads best on this color (9.82:1).
About this color
#51BFDB is a medium-light, moderately saturated teal or cyan. In OKLCH its lightness is 75%, its chroma 0.107 and its hue 217°. Its hue sits on the cool side of the wheel. The nearest named color is Vivid Sky Blue (#4CC9F0), ΔE 0.035 away. Black text reads best on it, at 9.82:1.
| Hue family | Teals and cyans |
| Lightness | medium-light (75%) |
| Chroma | moderately saturated (0.107) |
| Temperature | cool |
| Nearest name | Vivid Sky Blue (#4CC9F0) |
| Black text | 9.82:1 |
| White text | 2.13:1 |
Values
| HEX | #51BFDB |
| RGB | rgb(81, 191, 219) |
| HSL | hsl(192, 66%, 59%) |
| OKLCH | oklch(75.2% 0.107 217.5) |
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 #51BFDB | 2.13:1 | Fails | Lc -46.3 | Large or bold text, headings |
| Black text on #51BFDB | 9.82:1 | AAA | Lc 62.3 | Content text, not long reading |
| #51BFDB text on white | 2.13:1 | Fails | Lc 41.7 | Non-text elements, placeholder text |
| #51BFDB text on black | 9.82:1 | AAA | Lc -60.6 | 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 400.
-
Step 50
50
#EFF7F9
oklch(97.1% 0.009 214.3)
-
Step 100
100
#DCEDF2
oklch(93.5% 0.019 217.2)
-
Step 200
200
#BFE0E9
oklch(88.6% 0.037 216)
-
Step 300
300
#8FCCDD
oklch(81% 0.067 217)
-
Step 400
400 (this color)
#51BFDB
oklch(75.2% 0.107 217.5)
-
Step 500
500
#0099B6
oklch(63% 0.113 217.6)
-
Step 600
600
#008199
oklch(55.6% 0.099 216.9)
-
Step 700
700
#006C81
oklch(49% 0.088 217.4)
-
Step 800
800
#00596A
oklch(42.8% 0.076 216.6)
-
Step 900
900
#004A59
oklch(37.7% 0.067 217.2)
-
Step 950
950
#002C36
oklch(27% 0.048 217.4)
#51BFDB 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) | #ADBADD | 0.093 |
| Deuteranopia (no green cones) | #99ABDB | 0.084 |
| Tritanopia (no blue cones) | #00C9C8 | 0.053 |
| Achromatopsia (no color) | #B1B1B1 | 0.107 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #51BFDB
#51BFDB
oklch(75.2% 0.107 217.5)
- #E9967D
#E9967D
oklch(75.1% 0.107 37.5)
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 #51BFDB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Vivid Sky Blue #4CC9F0 ΔE 0.035
- Dark Turquoise #00CED1 ΔE 0.053
- Bright Sky Blue #02CCFE ΔE 0.054
- Deep Sky Blue #00BFFF ΔE 0.056
- Lightblue #7BC8F6 ΔE 0.059
- Turquoise Blue #06B1C4 ΔE 0.060
- Medium Turquoise #48D1CC ΔE 0.061
- Aqua Blue #02D8E9 ΔE 0.067
Use #51BFDB 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.