#40D9FF
Closest named color: Aqua Blue (#02D8E9). oklch(82.3% 0.134 218.7), rgb(64, 217, 255).
Aa
Black text reads best on this color (12.58:1).
About this color
#40D9FF is a light, moderately saturated teal or cyan. In OKLCH its lightness is 82%, its chroma 0.134 and its hue 219°. Its hue sits on the cool side of the wheel. The nearest named color is Aqua Blue (#02D8E9), ΔE 0.037 away. Black text reads best on it, at 12.58:1.
| Hue family | Teals and cyans |
| Lightness | light (82%) |
| Chroma | moderately saturated (0.134) |
| Temperature | cool |
| Nearest name | Aqua Blue (#02D8E9) |
| Black text | 12.58:1 |
| White text | 1.66:1 |
Values
| HEX | #40D9FF |
| RGB | rgb(64, 217, 255) |
| HSL | hsl(192, 100%, 63%) |
| OKLCH | oklch(82.3% 0.134 218.7) |
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 #40D9FF | 1.66:1 | Fails | Lc -32.6 | Non-text elements, placeholder text |
| Black text on #40D9FF | 12.58:1 | AAA | Lc 74.9 | Content text, not long reading |
| #40D9FF text on white | 1.66:1 | Fails | Lc 28.9 | Dividers and decoration only |
| #40D9FF text on black | 12.58:1 | AAA | Lc -73.9 | 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
#E9F9FE
oklch(97.2% 0.018 218.4)
-
Step 100
100
#CEF1FB
oklch(93.6% 0.039 216.9)
-
Step 200
200
#A1E6FA
oklch(88.6% 0.074 217.8)
-
Step 300
300 (this color)
#40D9FF
oklch(82.3% 0.134 218.7)
-
Step 400
400
#00B3D6
oklch(70.8% 0.128 218.5)
-
Step 500
500
#0099B8
oklch(63.1% 0.114 219)
-
Step 600
600
#00819B
oklch(55.7% 0.1 218.5)
-
Step 700
700
#006C82
oklch(49.1% 0.088 218.4)
-
Step 800
800
#00596B
oklch(42.8% 0.077 217.7)
-
Step 900
900
#004A5A
oklch(37.8% 0.068 218.5)
-
Step 950
950
#002C36
oklch(27% 0.048 217.4)
#40D9FF 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) | #C1D3FF | 0.113 |
| Deuteranopia (no green cones) | #A7C0FF | 0.101 |
| Tritanopia (no blue cones) | #00E6E5 | 0.061 |
| Achromatopsia (no color) | #C8C8C8 | 0.134 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #40D9FF
#40D9FF
oklch(82.3% 0.134 218.7)
- #FFAE94
#FFAE94
oklch(82.3% 0.102 38.5)
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 #40D9FF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Aqua Blue #02D8E9 ΔE 0.037
- Bright Sky Blue #02CCFE ΔE 0.042
- Vivid Sky Blue #4CC9F0 ΔE 0.043
- Light Sky Blue #87CEFA ΔE 0.053
- Lightblue #7BC8F6 ΔE 0.053
- Sky Blue #87CEEB ΔE 0.054
- Sky #82CAFC ΔE 0.055
- Robin's Egg #6DEDFD ΔE 0.066
Use #40D9FF 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.