Color

#666fa3

#666fa3
hex#666fa3
rgbrgb(102, 111, 163)
hslhsl(231, 25%, 52%)
oklchoklch(0.556 0.082 275.9)
Closest name: Loch Ness (#5f6db0)Relative luminance 0.1684

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#a39a66

#668ea3 · #7b66a3

#a3666f · #6fa366

Split-complementary

Open in tool →

#a37b66 · #8ea366

#a3668e · #a39a66 · #66a37b

Contrast

#666fa3 as textRatioAAAA largeAAAFix
Aaon white
4.81:1passpassfail
  • AAA: use #4e5683 as the text (7.04:1)
Aaon black
4.37:1failpassfail
  • AA: use #6972a5 as the text (4.55:1)
  • AAA: use #8f96bc as the text (7.26:1)
  • AA: or shift the background to #fafafa (4.61:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666fa3 as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

mcpConnect your agent — build around #666fa3
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — generate_palette, check_contrast, analyze_color — read-only, no key. Every palette it proposes comes with a /palettes/new/… link: open it, lock what you like, paste the link back.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #666fa3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/666fa3-9c9ec4-df834e-231f2d-e9eef1?lock=0&style=vibrant

Want the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.

Machine-readable: color.md