Color #666CBB Color / Colour Code #666CBB
This page shows the hex color code for color #666cbb (#666CBB). The colour is a blue tone with 38% saturation and 57% lightness. Explore its conversions, colour palettes, gradients, accessibility data, and CSS code below.
Color Conversions
Accessibility Contrast
WCAG contrast ratios for #666CBB against common backgrounds.
Complementary Colors
#666CBB paired with its color wheel opposite for maximum contrast.
Analogous Colors
Hues at 206, 236, and 266 degrees for harmonious combinations.
Triadic Palette
Three colors at 236, 356, and 116 degrees.
Color Palettes Using #666CBB
Five shades at lightness levels 15% through 85% while keeping hue at 236 and saturation at 38%. Use the darkest shade for text and the lightest for backgrounds to build a cohesive single-hue design system.
Adjacent hues from 236 to 281 degrees create a warm, unified palette. This analogous scheme works for marketing materials, seasonal campaigns, and any design that needs visual warmth without clashing colors.
Combines the base color at hue 236 with its complement at 56 and two adjacent cool tones. This split-complementary approach provides strong visual contrast while remaining more balanced than a pure complementary scheme.
Five evenly spaced hues at 40% saturation and 80% lightness. Pastels are gentle on the eyes and work well for dashboards, onboarding screens, category tags, and any interface where multiple distinct colors are needed without visual aggression.
Shades & Tints of #666CBB
Lightness variations at hue 236 and 38% saturation.
CSS Gradients with #666CBB
Design Use Cases for #666CBB
Balanced UI Color
At 38% saturation, #666CBB strikes a balance between vibrancy and restraint. This makes it versatile for primary UI elements like navigation bars, card headers, and form accents. It draws attention without overwhelming adjacent content.
Soft Accent & Highlight
With 57% lightness, #666CBB has a softer, more approachable quality. It works well for hover states, subtle highlights, progress indicators, and secondary UI elements. This lightness range is particularly effective for tag backgrounds and status indicators.
Trust & Professional Identity
#666CBB sits in the blue range (hue 236). Blue is the world's most popular color for corporate identities because it conveys trust, stability, and competence. Use it for navigation bars, link text, form focus states, and any element where user confidence matters. Financial, healthcare, and technology brands rely heavily on this hue range.
Gradient Pairing
Create a gradient from #666CBB (hue 236) to its complement at hue 56. For a subtler effect, try pairing with an analogous color at hue 266. Use CSS: background: linear-gradient(135deg, #666cbb, #bbb568);
CSS Code for #666CBB
Similar Colors
Colors visually similar to #666CBB based on RGB, lightness, and hue variations.
Use This Color in Design Tools
Apply #666CBB across image editing and color design tools.
About Color #666CBB (#666CBB)
#666CBB is a blue color (colour) with RGB channel values of 102 red, 108 green, and 187 blue. The blue channel is dominant with a relatively balanced channel distribution. In HSL terms, the hue sits at 236 degrees with 38% saturation and 57% lightness, placing it in the cool range of the colour spectrum.
The perceived brightness of #666CBB is 115/255 using the ITU-R BT.601 luma formula (0.299R + 0.587G + 0.114B). This appears dark to the human eye, so pair it with light text for adequate readability. For print production, the CMYK equivalent is 45% cyan, 42% magenta, 0% yellow, and 27% key (black).
The WCAG contrast ratio of #666CBB against white is 4.74:1 and against black is 4.43:1. This meets the AA requirement (4.5:1) for normal text on white. For AAA compliance, consider darkening to at least 40% lightness.
The complementary colour #BBB568 creates maximum visual tension when paired with #666CBB. For more harmonious color combinations, use the analogous colours #6897BB and #8C68BB, which sit 30 degrees on either side of the hue wheel. To build a complete design system, start with the monochromatic scale above for consistent shade variations, then add one complementary or triadic accent for interactive elements.
How to Explore Color #666CBB
- Enter your color value in HEX format.
- The tool converts it to RGB, HSL, CMYK format in real time.
- Copy the converted value to your clipboard.
What is HEX to RGB, HSL, CMYK color conversion
Converting from HEX to RGB, HSL, CMYK translates a color value between two different color models. Different color models are used in web design (HEX, RGB), print (CMYK), and color theory (HSL, HSV).
Related Tools & Colors
Frequently Asked Questions
- What color / colour is #666CBB?
- #666CBB is Color #666CBB, a blue color (colour) with RGB(102, 108, 187), HSL(236, 38%, 57%), and CMYK(45%, 42%, 0%, 27%). Its perceived brightness is 115/255.
- Is #666CBB accessible for text?
- Against white, #666CBB has a contrast ratio of 4.74:1 (passes AA for normal text). Against black, it has 4.43:1 (fails AA). Use the contrast checker tool for custom background pairings.
- What colours pair well with #666CBB?
- The complementary colour is #BBB568 (hue 56). For subtle color combinations, use analogous colours #6897BB and #8C68BB. The triadic palette adds #BB686D and #6DBB68 for vibrant variety.
- How do I use #666CBB in CSS?
- Use any format: color: #666cbb; or rgb(102, 108, 187); or hsl(236, 38%, 57%). For CSS custom properties: --color-primary: 236 38% 57%; then use it as hsl(var(--color-primary)).
- Is this color / colour explorer free?
- Yes, completely free with no signup required. All colour calculations run in your browser. You can explore any valid hex color code, not just the pre-generated palette.