Inspect Cyan (#00FFFF) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
Cyan
#00FFFF
Black text reads best on this background, at 16.75:1.
Cyan is one of the 148 CSS named colors, and resolves to #00FFFF in every browser. In numbers that is rgb(0, 255, 255) and hsl(180, 100%, 50%). Perceptually it is a very light, moderately saturated color: OKLCH puts its lightness at 91% and its chroma at 0.155. It sits in the cyans at 195 degrees of OKLCH hue, and reads as a cool color.
White text only reaches 1.25:1 here, so black text is the safer pairing at 16.75:1. Because it is this light, Cyan works best as a page or card background with dark text over it.
The closest CSS named colors to Cyan, measured with CIEDE2000, are Turquoise (#40E0D0), MediumTurquoise (#48D1CC), DarkTurquoise (#00CED1). If Cyan is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#00FFFF
RGB
rgb(0, 255, 255)
HSL
hsl(180, 100%, 50%)
HWB
hwb(180 0% 0%)
CMYK
cmyk(100%, 0%, 0%, 0%)
LAB
lab(90.67 -50.66 -14.96)
LCH
lch(90.67 52.82 196.45)
OKLCH
oklch(90.54% 0.1546 194.77)
WCAG asks for 4.5:1 between body text and its background. On #00FFFF white text measures 1.25:1 and black text 16.75:1, so black clears it and white does not.
White text on Cyan
WCAG 2.2
1.25:1
APCA
Lc 13
Fails AA body text
Fails AAA body text
Fails AA large text
Black text on Cyan
WCAG 2.2
16.75:1
APCA
Lc 91
Passes AA body text
Passes AAA body text
Passes AA large text
Check Cyan against any other color in the contrast checker.
Cyan sits at 91% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #E3FFFE and down to #000808, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#6AFFFE
20% lighter
#94FFFE
40% lighter
#B3FFFE
60% lighter
#CDFFFE
80% lighter
#E3FFFE
100% lighter
#00C6C6
20% darker
#009090
40% darker
#005D5D
60% darker
#002F2F
80% darker
#000808
100% darker
Build a full accessible scale from #00FFFF in the shade generator.
Hues rotated around #00FFFF in OKLCH, then pulled back into the sRGB gamut. Each swatch is labelled with the nearest CSS named color so you have a keyword to start from.
Cyan sits at 195 degrees. Rotating it a half turn lands on 15 degrees, the hue directly opposite. It is the strongest pairing you can make without changing lightness, and the one most likely to vibrate if you use both at full chroma.
The neighbors of Cyan at 165 and 225 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
195, 315 and 75 degrees divide the wheel into thirds. Balanced enough to carry a whole palette without one color dominating the other two.
Instead of the complement at 15 degrees, this pair flanks it at 345 and 45. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around Cyan on the color wheel.
The biggest shift is under deuteranopia, where #00FFFF reads as #A1B8FF, 32.4 CIEDE2000 units away. If Cyan is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#D8E2FF
Deuteranopia
#A1B8FF
Tritanopia
#00FFFE
Achromatopsia
#C9C9C9
The nearest CSS keywords to #00FFFF, ranked by perceptual distance rather than by how close their hex digits happen to look.