Color

#123ea5

#123ea5
hex#123ea5
rgbrgb(18, 62, 165)
hslhsl(222, 80%, 36%)
oklchoklch(0.408 0.173 263.3)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0629

Colors that go with #123ea5

Charcoal, Crimson and Steel Blue 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 →

#a57912

#1288a5 · #3012a5

#a5123e · #3ea512

Split-complementary

Open in tool →

#a53012 · #88a512

#a51288 · #a57912 · #12a530

Contrast

#123ea5 as textRatioAAAA largeAAAFix
Aaon white
9.3:1passpasspassPasses AAA — no fix needed.
Aaon black
2.26:1failfailfail
  • AA: use #3a6ee9 as the text (4.59:1)
  • AAA: use #6c93ef as the text (7.06:1)
  • AA: or shift the background to #b5b5b5 (4.54:1)
  • AAA: or shift the background to #e0e0e0 (7.04:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #123ea5 as the background.

Brands using this color

Fonts for this mood

#123ea5 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #123ea5
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 #123ea5 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/123ea5-9ca3c4-df6e4e-211f2d-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