Color

#666bf4

#666bf4
hex#666bf4
rgbrgb(102, 107, 244)
hslhsl(238, 87%, 68%)
oklchoklch(0.598 0.201 276.9)
Closest name: mediumslateblue (#7b68ee)Relative luminance 0.1987

Tints & shades

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

Harmonies

Complementary

Open in tool →

#f4f066

#66b2f4 · #a966f4

#f4666b · #6bf466

Split-complementary

Open in tool →

#f4a966 · #b2f466

#f466b2 · #f4f066 · #66f4a9

Contrast

#666bf4 as textRatioAAAA largeAAAFix
Aaon white
4.22:1failpassfail
  • AA: use #5d62f4 as the text (4.65:1)
  • AAA: use #3238f1 as the text (7.07:1)
  • AA: or shift the background to #0f0f0f (4.54:1)
Aaon black
4.97:1passpassfail
  • AAA: use #888bf7 as the text (7.08:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666bf4 as the background.

Brands using this color

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

Fonts for this mood

#666bf4 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #666bf4
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 #666bf4 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/666bf4-9f9cc4-df944e-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