#66ADDD
Closest named color: Greyblue (#77A1B5). oklch(72% 0.1 239.8), rgb(102, 173, 221).
Aa
Black text reads best on this color (8.58:1).
About this color
#66ADDD is a medium-light, moderately saturated blue. In OKLCH its lightness is 72%, its chroma 0.100 and its hue 240°. Its hue sits on the cool side of the wheel. The nearest named color is Greyblue (#77A1B5), ΔE 0.059 away. Black text reads best on it, at 8.58:1.
| Hue family | Blues |
| Lightness | medium-light (72%) |
| Chroma | moderately saturated (0.100) |
| Temperature | cool |
| Nearest name | Greyblue (#77A1B5) |
| Black text | 8.58:1 |
| White text | 2.44:1 |
Values
| HEX | #66ADDD |
| RGB | rgb(102, 173, 221) |
| HSL | hsl(204, 64%, 63%) |
| OKLCH | oklch(72% 0.1 239.8) |
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 #66ADDD | 2.44:1 | Fails | Lc -53.0 | Large or bold text, headings |
| Black text on #66ADDD | 8.58:1 | AAA | Lc 56.0 | Large or bold text, headings |
| #66ADDD text on white | 2.44:1 | Fails | Lc 48.0 | Large or bold text, headings |
| #66ADDD text on black | 8.58:1 | AAA | Lc -54.0 | 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
#F1F6FB
oklch(97.1% 0.009 247.9)
-
Step 100
100
#DFECF5
oklch(93.6% 0.018 237.8)
-
Step 200
200
#C5DDEE
oklch(88.5% 0.035 238.7)
-
Step 300
300
#9CC7E5
oklch(80.9% 0.062 239)
-
Step 400
400 (this color)
#66ADDD
oklch(72% 0.1 239.8)
-
Step 500
500
#2B92CE
oklch(63% 0.128 239.8)
-
Step 600
600
#007BB5
oklch(55.6% 0.127 239.8)
-
Step 700
700
#006799
oklch(49% 0.112 240)
-
Step 800
800
#00557E
oklch(42.8% 0.097 239.2)
-
Step 900
900
#044669
oklch(37.6% 0.084 240.1)
-
Step 950
950
#08293D
oklch(26.9% 0.053 239.9)
#66ADDD 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) | #98ADDF | 0.056 |
| Deuteranopia (no green cones) | #87A0DC | 0.047 |
| Tritanopia (no blue cones) | #11B9BD | 0.081 |
| Achromatopsia (no color) | #A6A6A6 | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #66ADDD
#66ADDD
oklch(72% 0.1 239.8)
- #D39562
#D39562
oklch(71.9% 0.1 59.7)
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 #66ADDD, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Greyblue #77A1B5 ΔE 0.059
- Bluegrey #85A3B2 ΔE 0.065
- Deep Sky Blue #00BFFF ΔE 0.066
- Turquoise Blue #06B1C4 ΔE 0.066
- Carolina Blue #8AB8FE ΔE 0.068
- Bluey Grey #89A0B0 ΔE 0.071
- Vivid Sky Blue #4CC9F0 ΔE 0.074
- Cool Steel #97A7B3 ΔE 0.075
Use #66ADDD 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.