Color

#664ec6

#664ec6
hex#664ec6
rgbrgb(102, 78, 198)
hslhsl(252, 51%, 54%)
oklchoklch(0.515 0.179 287.6)
Closest name: slateblue (#6a5acd)Relative luminance 0.1235

Colors that go with #664ec6

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 →

#aec64e

#4e72c6 · #a24ec6

#c6664e · #4ec666

Split-complementary

Open in tool →

#c6a24e · #72c64e

#c64e72 · #aec64e · #4ec6a2

Contrast

#664ec6 as textRatioAAAA largeAAAFix
Aaon white
6.05:1passpassfail
  • AAA: use #583ec1 as the text (7.31:1)
Aaon black
3.47:1failpassfail
  • AA: use #7a65cd as the text (4.57:1)
  • AAA: use #9b8bda as the text (7.1:1)
  • AA: or shift the background to #e0e0e0 (4.58:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #664ec6 as the background.

Brands using this color

Fonts for this mood

#664ec6 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #664ec6
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 #664ec6 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/664ec6-a99cc4-dfb64e-281f2d-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