Color

#123fc4

#123fc4
hex#123fc4
rgbrgb(18, 63, 196)
hslhsl(225, 83%, 42%)
oklchoklch(0.44 0.211 264.3)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0767

Colors that go with #123fc4

Charcoal, Steel Blue 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 →

#c49812

#1298c4 · #3f12c4

#c4123f · #3fc412

Split-complementary

Open in tool →

#c43f12 · #98c412

#c41298 · #c49812 · #12c43f

Contrast

#123fc4 as textRatioAAAA largeAAAFix
Aaon white
8.29:1passpasspassPasses AAA — no fix needed.
Aaon black
2.53:1failfailfail
  • AA: use #406bed as the text (4.54:1)
  • AAA: use #7393f2 as the text (7.18:1)
  • AA: or shift the background to #bfbfbf (4.51:1)
  • AAA: or shift the background to #ededed (7.08:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #123fc4 as the background.

Brands using this color

Fonts for this mood

#123fc4 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #123fc4
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 #123fc4 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/123fc4-9ca1c4-df754e-221f2d-e9eff1?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