Color

#31b5dd

#31b5dd
hex#31b5dd
rgbrgb(49, 181, 221)
hslhsl(194, 72%, 53%)
oklchoklch(0.721 0.123 223.4)
Closest name: Blue Martini (#52b4d3)Relative luminance 0.3892

Colors that go with #31b5dd

Charcoal, Amber and Dark Orange 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 →

#dd5931

#31ddaf · #315fdd

#dd31b5 · #b5dd31

Split-complementary

Open in tool →

#dd315f · #ddaf31

#af31dd · #dd5931 · #5fdd31

Contrast

#31b5dd as textRatioAAAA largeAAAFix
Aaon white
2.39:1failfailfail
  • AA: use #1a7f9e as the text (4.59:1)
  • AAA: use #135f76 as the text (7.18:1)
  • AA: or shift the background to #3d3d3d (4.54:1)
  • AAA: or shift the background to #1c1c1c (7.13:1)
Aaon black
8.78:1passpasspassPasses 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 #31b5dd as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#31b5dd reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #31b5dd
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 #31b5dd and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/31b5dd-9cb6c4-df4e72-1f242d-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