Color

#665ec5

#665ec5
hex#665ec5
rgbrgb(102, 94, 197)
hslhsl(245, 47%, 57%)
oklchoklch(0.542 0.155 283.4)
Closest name: slateblue (#6a5acd)Relative luminance 0.1486

Colors that go with #665ec5

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 →

#bcc55e

#5e89c5 · #9a5ec5

#c5665e · #5ec566

Split-complementary

Open in tool →

#c59a5e · #89c55e

#c55e89 · #bcc55e · #5ec59a

Contrast

#665ec5 as textRatioAAAA largeAAAFix
Aaon white
5.29:1passpassfail
  • AAA: use #5147bd as the text (7.03:1)
Aaon black
3.97:1failpassfail
  • AA: use #7169c9 as the text (4.57:1)
  • AAA: use #958fd6 as the text (7.18:1)
  • AA: or shift the background to #ededed (4.52:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #665ec5 as the background.

Brands using this color

Fonts for this mood

#665ec5 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #665ec5
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 #665ec5 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/665ec5-a49cc4-dfa54e-261f2d-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