#003666 Color

#003666 is rgb(0, 54, 102) in RGB, hsl(208, 100%, 20%) in HSL, and about cmyk(100%, 47%, 0%, 60%) in CMYK. It has no registered color name of its own — the closest is Marine Blue (#01386A), below the threshold most people can see at ΔE 1.46. White text is the more readable choice on this background.

#003666

HEX#003666

RGBrgb(0, 54, 102)

HSLhsl(208, 100%, 20%)

HSVhsv(208, 100%, 40%)

CMYKcmyk(100%, 47%, 0%, 60%)

OKLCHoklch(33.1% 0.099 251.9)

LABlab(21.76% -0.08 -33.36)

LCHlch(21.76% 33.36 269.86)

What #003666 Is Called

Most hex codes have no name: there are 16.7 million of them and a few thousand registered names. These are the named colors nearest to #003666, ordered by CIE76 distance in CIELAB. Anything under about ΔE 2 is a difference most people cannot see.

Marine Blue#01386AΔE 1.46 Dark Midnight Blue#003366ΔE 2.75 Yale Blue#00356BΔE 4.15 Indigo Dye#00416AΔE 7.71 Prussian Blue#003153ΔE 9.32 Space Cadet#1D2951ΔE 10.04

Browse the full index of named colors A-Z or every blue in the library.

#003666 Channel Values

How #003666 breaks down in each color model. Hue is measured in degrees around the color wheel; saturation, lightness, and the CMYK inks are percentages.

Model	Channels	Notes
RGB	R 0 · G 54 · B 102	8-bit channels as sent to the display
HSL	H 208° · S 100% · L 20%	Easiest model for building lighter and darker variants
HSV	H 208° · S 100% · V 40%	Matches the picker in most design tools
CMYK	C 100% · M 47% · Y 0% · K 60%	Approximate ink mix; confirm with an ICC profile before printing
Luminance	12.21:1 vs white · 1.72:1 vs black	WCAG 2.2 relative-luminance contrast ratios

Text Contrast & Accessibility

WCAG 2.2 contrast ratios for text on a #003666 background. AA requires 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Contrast is one check, not a full accessibility review.

TextWhite text12.21:1AA normal AA large AAA normal

Fails AABlack text1.72:1AA normal AA large AAA normal

Need a specific ratio against another background? Open #003666 in the contrast checker.

Colors That Go With #003666

Pairings derived from color-wheel relationships. The complementary color sits opposite #003666; analogous colors sit beside it; triadic and split-complementary sets spread evenly around the wheel. Select any swatch for its own breakdown.

Base

Complementary

Analogous

Analogous

Triadic

Triadic

Split comp.

Split comp.

Tints & Shades of #003666

Lighter tints and darker shades built by moving the lightness channel while holding hue and saturation, which is what you want for hover states, backgrounds, and text variants.

Tints

Shades

Want a full 50-950 ramp with semantic roles? Generate design tokens from #003666.

How #003666 Looks with Color Vision Deficiency

Simulated with the Viénot, Brettel & Mollon LMS projection model. Anomalous types are rendered as partial versions of the matching dichromacy, which is an approximation rather than a per-person clinical model.

Typical#003666

Protanopia#313166

Protanomaly#253366

Deuteranopia#2C2C66

Deuteranomaly#203066

Tritanopia#003F3F

Tritanomaly#003B51

Achromatopsia#353535

Test a full palette in the color blindness simulator.

Using #003666 in Code

Copy-ready declarations for the places this color usually ends up.

CSS custom property--color-003666: #003666;

CSS backgroundbackground-color: #003666;

Tailwind configcolors: { 'color-003666': '#003666' }

SwiftUIColor(red: 0.000, green: 0.212, blue: 0.400)

Android XML<color name="color_003666">#003666</color>

SVG fillfill="#003666"

More Blue Colors

#003666 sits in the blue family. These are its neighbours across that family's full range, each with its own breakdown.

000024 fafaff 00002e f9fafb 000033 f8fafc 000038 f8f8ff 000042 f5faff 000047 f5f5ff 002147 007dfa 0f52ba 1c39bb 2a3439 372aac 4e3cc3 64609a 7abdff 979aaa b8dbff d6d6ff

#003666 Frequently Asked Questions

What color is #003666?

#003666 is a dark blue — rgb(0, 54, 102) in RGB and hsl(208, 100%, 20%) in HSL. It carries no registered color name of its own; the closest named color is Marine Blue (#01386A), which is below the threshold most people can see at a CIE76 distance of 1.46.

What is the RGB value of #003666?

#003666 is rgb(0, 54, 102) — red 0, green 54, and blue 102 on the 0-255 scale.

What is the CMYK value of #003666?

#003666 converts to approximately cmyk(100%, 47%, 0%, 60%). CMYK output is a mathematical approximation for planning; confirm production print colors with your printer and ICC profile.

Should text on #003666 be black or white?

White text is the more readable choice. #003666 scores 12.21:1 against white and 1.72:1 against black, and WCAG 2.2 asks for at least 4.5:1 for normal body text.

Can I write #003666 as a CSS color keyword?

No. #003666 is not one of the CSS color keywords, so it has to be written as a hex, rgb() or hsl() value. The closest keyword is darkslateblue (#483D8B) at a CIE76 distance of 24.95, which is visibly different.

Open #003666 in a Tool

Hex to RGB Hex to HSL Hex to CMYK Hex to OKLCH Hex to Pantone Build a palette Make a gradient

Keep exploring: every blue in the color library, the guide to shades of blue, or the full color library.