Color

#663bb0

#663bb0
hex#663bb0
rgbrgb(102, 59, 176)
hslhsl(262, 50%, 46%)
oklchoklch(0.469 0.177 295.7)
Closest name: rebeccapurple (#663399)Relative luminance 0.0909

Colors that go with #663bb0

Olive Green, Sea Green and Charcoal 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 →

#85b03b

#3b4ab0 · #a03bb0

#b0663b · #3bb066

Split-complementary

Open in tool →

#b0a03b · #4ab03b

#b03b4a · #85b03b · #3bb0a0

Contrast

#663bb0 as textRatioAAAA largeAAAFix
Aaon white
7.45:1passpasspassPasses AAA — no fix needed.
Aaon black
2.82:1failfailfail
  • AA: use #8962cb as the text (4.67:1)
  • AAA: use #a588d7 as the text (7.1:1)
  • AA: or shift the background to #c9c9c9 (4.5:1)
  • AAA: or shift the background to #fafafa (7.14:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #663bb0 as the background.

Brands using this color

Fonts for this mood

#663bb0 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #663bb0
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 #663bb0 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/663bb0-af9cc4-dfce4e-2a1f2d-e9eaf1?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