#66FDF9
Closest named color: Bright Cyan (#41FDFE). oklch(91.3% 0.128 192.7), rgb(102, 253, 249).
Aa
Black text reads best on this color (16.98:1).
About this color
#66FDF9 is a very light, moderately saturated teal or cyan. In OKLCH its lightness is 91%, its chroma 0.128 and its hue 193°. Its hue sits on the cool side of the wheel. The nearest named color is Bright Cyan (#41FDFE), ΔE 0.018 away. Black text reads best on it, at 16.98:1.
| Hue family | Teals and cyans |
| Lightness | very light (91%) |
| Chroma | moderately saturated (0.128) |
| Temperature | cool |
| Nearest name | Bright Cyan (#41FDFE) |
| Black text | 16.98:1 |
| White text | 1.23:1 |
Values
| HEX | #66FDF9 |
| RGB | rgb(102, 253, 249) |
| HSL | hsl(178, 97%, 70%) |
| OKLCH | oklch(91.3% 0.128 192.7) |
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 #66FDF9 | 1.23:1 | Fails | Lc -13.2 | Not readable |
| Black text on #66FDF9 | 16.98:1 | AAA | Lc 92.2 | Preferred for body text |
| #66FDF9 text on white | 1.23:1 | Fails | Lc 11.4 | Not readable |
| #66FDF9 text on black | 16.98:1 | AAA | Lc -92.7 | Preferred for body text |
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 100.
-
Step 50
50
#E6FAF9
oklch(97% 0.021 193.2)
-
Step 100
100 (this color)
#66FDF9
oklch(91.3% 0.128 192.7)
-
Step 200
200
#8DEDE9
oklch(88.6% 0.091 192.2)
-
Step 300
300
#00DCD9
oklch(80.9% 0.139 193)
-
Step 400
400
#00B8B5
oklch(70.8% 0.121 192.7)
-
Step 500
500
#009E9B
oklch(63.2% 0.108 192.4)
-
Step 600
600
#008482
oklch(55.5% 0.095 192.9)
-
Step 700
700
#006F6E
oklch(49% 0.084 193.7)
-
Step 800
800
#005B5A
oklch(42.6% 0.073 193.5)
-
Step 900
900
#004C4B
oklch(37.7% 0.064 193.2)
-
Step 950
950
#002D2C
oklch(26.9% 0.046 192.5)
#66FDF9 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) | #EFF1F9 | 0.135 |
| Deuteranopia (no green cones) | #D7E0FA | 0.125 |
| Tritanopia (no blue cones) | #00FFFB | 0.029 |
| Achromatopsia (no color) | #E7E7E7 | 0.129 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #66FDF9
#66FDF9
oklch(91.3% 0.128 192.7)
- #FFD7DA
#FFD7DA
oklch(91.4% 0.045 12.9)
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 #66FDF9, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Bright Cyan #41FDFE ΔE 0.018
- Bright Turquoise #0FFEF9 ΔE 0.028
- Cyan #00FFFF ΔE 0.028
- Bright Light Blue #26F7FD ΔE 0.034
- Bright Aqua #0BF9EA ΔE 0.041
- Robin Egg Blue #8AF1FE ΔE 0.042
- Robin's Egg #6DEDFD ΔE 0.046
- Light Aqua #8CFFDB ΔE 0.048
Use #66FDF9 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.