Color

#3fb1fd

#3fb1fd
hex#3fb1fd
rgbrgb(63, 177, 253)
hslhsl(204, 98%, 62%)
oklchoklch(0.73 0.149 242.5)
Closest name: Cerulean (#55aaee)Relative luminance 0.3959

Colors that go with #3fb1fd

Charcoal, Dark Orange 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 →

#fd8b3f

#3ffdea · #3f52fd

#fd3fb1 · #b1fd3f

Split-complementary

Open in tool →

#fd3f52 · #fdea3f

#ea3ffd · #fd8b3f · #52fd3f

Contrast

#3fb1fd as textRatioAAAA largeAAAFix
Aaon white
2.35:1failfailfail
  • AA: use #027aca as the text (4.53:1)
  • AAA: use #025b97 as the text (7.13:1)
  • AA: or shift the background to #3d3d3d (4.61:1)
  • AAA: or shift the background to #1f1f1f (7:1)
Aaon black
8.92:1passpasspassPasses 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 #3fb1fd as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#3fb1fd reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3fb1fd
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 #3fb1fd and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3fb1fd-9cafc4-df4e5a-1f222d-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