Color

#5151c8

#5151c8
hex#5151c8
rgbrgb(81, 81, 200)
hslhsl(240, 52%, 55%)
oklchoklch(0.505 0.18 277.8)
Closest name: slateblue (#6a5acd)Relative luminance 0.118

Colors that go with #5151c8

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 →

#c8c851

#518cc8 · #8c51c8

#c85151 · #51c851

Split-complementary

Open in tool →

#c88c51 · #8cc851

#c8518c · #c8c851 · #51c88c

Contrast

#5151c8 as textRatioAAAA largeAAAFix
Aaon white
6.25:1passpassfail
  • AAA: use #4545c4 as the text (7.24:1)
Aaon black
3.36:1failpassfail
  • AA: use #6c6cd0 as the text (4.69:1)
  • AAA: use #8f8fdc as the text (7.13:1)
  • AA: or shift the background to #dbdbdb (4.51:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #5151c8 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

#5151c8 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #5151c8
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 #5151c8 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/5151c8-a19cc4-df994e-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