#3666CE
≈ royalblue · rgb(54, 102, 206)
Color formats
HEX#3666CE
RGBrgb(54, 102, 206)
HSLhsl(221, 61%, 51%)
HSVhsv(221, 74%, 81%)
OKLCHoklch(54% 0.17 263)
CMYKcmyk(74%, 50%, 0%, 19%)
Contrast & accessibility
On white5.32:1AA pass
On black3.95:1below AA
Best text color#FFFFFF
Nearest CSS name: royalblue
Copy-ready code
CSS custom properties
:root {
--royalblue: #3666ce;
--royalblue-rgb: 54 102 206;
--royalblue-oklch: oklch(54% 0.17 263);
}The space-separated triple lets you set alpha without a second variable:
background: rgb(var(--royalblue-rgb) / 40%);
Tailwind (arbitrary value)
bg-[#3666ce] text-[#3666ce] border-[#3666ce]
Shades & tints
Color harmonies
About this color
#3666CE is a color with the RGB value rgb(54, 102, 206). Its closest CSS named color is "royalblue". On this page you'll find every format (HEX, RGB, HSL, HSV, OKLCH, CMYK), WCAG contrast against white and black, a full 50–950 shade scale, and complementary, analogous and triadic harmonies — each linking to its own color page.