Color

#51636c

#51636c
hex#51636c
rgbrgb(81, 99, 108)
hslhsl(200, 14%, 37%)
oklchoklch(0.488 0.026 229.6)
Closest name: Concrete Landscape (#5c606e)Relative luminance 0.1176

Colors that go with #51636c

Charcoal, Blush Pink and Cadet Blue 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 →

#6c5a51

#516c67 · #51566c

#6c5163 · #636c51

Split-complementary

Open in tool →

#6c5156 · #6c6751

#67516c · #6c5a51 · #566c51

Contrast

#51636c as textRatioAAAA largeAAAFix
Aaon white
6.27:1passpassfail
  • AAA: use #4b5b63 as the text (7.06:1)
Aaon black
3.35:1failpassfail
  • AA: use #637883 as the text (4.54:1)
  • AAA: use #8599a3 as the text (7.08:1)
  • AA: or shift the background to #dbdbdb (4.53:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #51636c as the background.

Brands using this color

mcpConnect your agent — build around #51636c
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 #51636c and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/51636c-9cb2c4-df4e64-1f232d-e9f1f0?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