Color

#0b40bc

#0b40bc
hex#0b40bc
rgbrgb(11, 64, 188)
hslhsl(222, 89%, 39%)
oklchoklch(0.432 0.201 263.2)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0737

Colors that go with #0b40bc

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 →

#bc870b

#0b99bc · #2e0bbc

#bc0b40 · #40bc0b

Split-complementary

Open in tool →

#bc2e0b · #99bc0b

#bc0b99 · #bc870b · #0bbc2e

Contrast

#0b40bc as textRatioAAAA largeAAAFix
Aaon white
8.49:1passpasspassPasses AAA — no fix needed.
Aaon black
2.47:1failfailfail
  • AA: use #356ef3 as the text (4.68:1)
  • AAA: use #6a94f6 as the text (7.18:1)
  • AA: or shift the background to #bdbdbd (4.52:1)
  • AAA: or shift the background to #ebebeb (7.12:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #0b40bc as the background.

Brands using this color

Fonts for this mood

#0b40bc reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #0b40bc
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 #0b40bc and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/0b40bc-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