Color

#666ba3

#666ba3
hex#666ba3
rgbrgb(102, 107, 163)
hslhsl(235, 25%, 52%)
oklchoklch(0.547 0.087 279.2)
Closest name: Loch Ness (#5f6db0)Relative luminance 0.1598

Colors that go with #666ba3

Charcoal, Amber and Cobalt Blue lead the list. Each partner is a real named colour with the reason it works — a wheel relationship, a neutral that carries it, or a pairing lifted from a palette or brand system that actually shipped — and every pair opens in the palette tool.

Tints & shades

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

Harmonies

Complementary

Open in tool →

#a39e66

#668aa3 · #8066a3

#a3666b · #6ba366

Split-complementary

Open in tool →

#a38066 · #8aa366

#a3668a · #a39e66 · #66a380

Contrast

#666ba3 as textRatioAAAA largeAAAFix
Aaon white
5:1passpassfail
  • AAA: use #505586 as the text (7.04:1)
Aaon black
4.2:1failpassfail
  • AA: use #6c71a7 as the text (4.56:1)
  • AAA: use #8f93bc as the text (7.07:1)
  • AA: or shift the background to #f5f5f5 (4.59:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666ba3 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 #666ba3
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — direct_palette, edit_direction, check_palette, check_contrast — read-only, no key. Every direction it proposes comes with a /colors/d/… link: open it, lock what you like, paste the link back, and the agent edits rather than re-rolls.

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

analyze #666ba3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/666ba3-9e9cc4-df8d4e-241f2d-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