Color

#666ef9

#666ef9
hex#666ef9
rgbrgb(102, 110, 249)
hslhsl(237, 92%, 69%)
oklchoklch(0.607 0.204 276)
Closest name: Blue Öyster Cult (#5577ee)Relative luminance 0.2082

Tints & shades

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

Harmonies

Complementary

Open in tool →

#f9f167

#67b7f9 · #a967f9

#f9676e · #6ef967

Split-complementary

Open in tool →

#f9a967 · #b7f967

#f967b7 · #f9f167 · #67f9a9

Contrast

#666ef9 as textRatioAAAA largeAAAFix
Aaon white
4.07:1failpassfail
  • AA: use #5961f8 as the text (4.68:1)
  • AAA: use #2c37f6 as the text (7.04:1)
  • AA: or shift the background to #141414 (4.53:1)
Aaon black
5.16:1passpassfail
  • AAA: use #858afa as the text (7.01:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666ef9 as the background.

Brands using this color

Fonts for this mood

#666ef9 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #666ef9
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 #666ef9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/666ef9-9f9cc4-df924e-251f2d-e9edf1?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