Dark Blue-gray (#666699)
The hex code for Dark Blue-gray is #666699. It is rgb(102, 102, 153) in RGB, hsl(240, 20%, 50%) in HSL, and about cmyk(33%, 33%, 0%, 40%) in CMYK — a mid-tone blue. White text is the more readable choice on this background.
#666699rgb(102, 102, 153)hsl(240, 20%, 50%)hsv(240, 33%, 60%)cmyk(33%, 33%, 0%, 40%)oklch(53.2% 0.079 283.4)lab(44.82% 9.53 -28.06)lch(44.82% 29.64 288.76)Colors Closest to Dark Blue-gray
Dark Blue-gray is a registered color name. These are the named colors nearest to it, measured as CIE76 distance in CIELAB — a perceptual scale, so the ordering matches what the eye sees rather than how close the raw RGB numbers happen to sit.
Browse the full index of named colors A-Z or every blue in the library.
#666699 Channel Values
How Dark Blue-gray 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 102 · G 102 · B 153 | 8-bit channels as sent to the display |
| HSL | H 240° · S 20% · L 50% | Easiest model for building lighter and darker variants |
| HSV | H 240° · S 33% · V 60% | Matches the picker in most design tools |
| CMYK | C 33% · M 33% · Y 0% · K 40% | Approximate ink mix; confirm with an ICC profile before printing |
| Luminance | 5.35:1 vs white · 3.93:1 vs black | WCAG 2.2 relative-luminance contrast ratios |
Text Contrast & Accessibility
WCAG 2.2 contrast ratios for text on a Dark Blue-gray 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.
Need a specific ratio against another background? Open #666699 in the contrast checker.
Colors That Go With Dark Blue-gray
Pairings derived from color-wheel relationships. The complementary color sits opposite Dark Blue-gray; analogous colors sit beside it; triadic and split-complementary sets spread evenly around the wheel. Select any swatch for its own breakdown.
Tints & Shades of Dark Blue-gray
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.
Want a full 50-950 ramp with semantic roles? Generate design tokens from #666699.
How Dark Blue-gray 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.
#666699#666699#666699#666699#666699#5D6E6E#616B81#6B6B6BUsing #666699 in Code
Copy-ready declarations for the places this color usually ends up.
--dark-blue-gray: #666699;background-color: #666699;colors: { 'dark-blue-gray': '#666699' }Color(red: 0.400, green: 0.400, blue: 0.600)<color name="dark_blue_gray">#666699</color>fill="#666699"More Blue Colors
Dark Blue-gray sits in the blue family. These are its neighbours across that family's full range, each with its own breakdown.
#666699 Frequently Asked Questions
What is the hex code for Dark Blue-gray?
The hex code for Dark Blue-gray is #666699. That is rgb(102, 102, 153) in RGB, hsl(240, 20%, 50%) in HSL, and approximately cmyk(33%, 33%, 0%, 40%) in CMYK.
What is the RGB value of #666699?
#666699 is rgb(102, 102, 153) — red 102, green 102, and blue 153 on the 0-255 scale.
What is the CMYK value of #666699?
#666699 converts to approximately cmyk(33%, 33%, 0%, 40%). CMYK output is a mathematical approximation for planning; confirm production print colors with your printer and ICC profile.
Should text on #666699 be black or white?
White text is the more readable choice. #666699 scores 5.35:1 against white and 3.93:1 against black, and WCAG 2.2 asks for at least 4.5:1 for normal body text.
Can I write #666699 as a CSS color keyword?
No. #666699 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 steelblue (#4682B4) at a CIE76 distance of 19.85, which is visibly different.
Open Dark Blue-gray in a Tool
Keep exploring: every blue in the color library, the guide to shades of blue, or the full color library.