Color

#51b8cd

#51b8cd
hex#51b8cd
rgbrgb(81, 184, 205)
hslhsl(190, 55%, 56%)
oklchoklch(0.73 0.099 213.2)
Closest name: Blue Bobbin (#52b4ca)Relative luminance 0.4044

Colors that go with #51b8cd

Charcoal, Blue and Crimson 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 →

#cd6651

#51cda3 · #517acd

#cd51b8 · #b8cd51

Split-complementary

Open in tool →

#cd517a · #cda351

#a351cd · #cd6651 · #7acd51

Contrast

#51b8cd as textRatioAAAA largeAAAFix
Aaon white
2.31:1failfailfail
  • AA: use #2a8192 as the text (4.51:1)
  • AAA: use #1f5e6b as the text (7.31:1)
  • AA: or shift the background to #3d3d3d (4.7:1)
  • AAA: or shift the background to #1f1f1f (7.13:1)
Aaon black
9.09:1passpasspassPasses AAA — no fix needed.

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #51b8cd 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

#51b8cd reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #51b8cd
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 #51b8cd and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/51b8cd-a2b6be-df4e7c-1f252d-e9f1ef?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