Color

#66637e

#66637e
hex#66637e
rgbrgb(102, 99, 126)
hslhsl(247, 12%, 44%)
oklchoklch(0.513 0.042 289.9)
Closest name: Alley Cat (#656874)Relative luminance 0.1325

Colors that go with #66637e

Charcoal, Sea Green and Amber 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 →

#7b7e63

#636d7e · #73637e

#7e6663 · #637e66

Split-complementary

Open in tool →

#7e7363 · #6d7e63

#7e636d · #7b7e63 · #637e73

Contrast

#66637e as textRatioAAAA largeAAAFix
Aaon white
5.75:1passpassfail
  • AAA: use #58556d as the text (7.15:1)
Aaon black
3.65:1failpassfail
  • AA: use #777391 as the text (4.65:1)
  • AAA: use #9895ac as the text (7.23:1)
  • AA: or shift the background to #e6e6e6 (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 #66637e 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 #66637e
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 #66637e and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/66637e-a59cc4-dfaa4e-271f2d-e9ecf1?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