Color

#51646c

#51646c
hex#51646c
rgbrgb(81, 100, 108)
hslhsl(198, 14%, 37%)
oklchoklch(0.49 0.026 225.3)
Closest name: Concrete Landscape (#5c606e)Relative luminance 0.1195

Colors that go with #51646c

Charcoal, Champagne and Copper 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 →

#6c5951

#516c66 · #51566c

#6c5164 · #646c51

Split-complementary

Open in tool →

#6c5156 · #6c6651

#66516c · #6c5951 · #566c51

Contrast

#51646c as textRatioAAAA largeAAAFix
Aaon white
6.2:1passpassfail
  • AAA: use #485960 as the text (7.31:1)
Aaon black
3.39:1failpassfail
  • AA: use #637983 as the text (4.59:1)
  • AAA: use #859aa3 as the text (7.15:1)
  • AA: or shift the background to #dedede (4.61:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #51646c as the background.

Brands using this color

mcpConnect your agent — build around #51646c
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 #51646c and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/51646c-9cb3c4-df4e69-1f232d-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