Color

#040d8b

#040d8b
hex#040d8b
rgbrgb(4, 13, 139)
hslhsl(236, 94%, 28%)
oklchoklch(0.299 0.192 265.1)
Closest name: darkblue (#00008b)Relative luminance 0.0218

Colors that go with #040d8b

Steel Blue, Charcoal and Cobalt 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 →

#8b8204

#04508b · #3e048b

#8b040d · #0d8b04

Split-complementary

Open in tool →

#8b3e04 · #508b04

#8b0450 · #8b8204 · #048b3e

Contrast

#040d8b as textRatioAAAA largeAAAFix
Aaon white
14.63:1passpasspassPasses AAA — no fix needed.
Aaon black
1.44:1failfailfail
  • AA: use #5762fa as the text (4.53:1)
  • AAA: use #838bfb as the text (7.05:1)
  • AA: or shift the background to #8f8f8f (4.52:1)
  • AAA: or shift the background to #b5b5b5 (7.13:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #040d8b as the background.

Brands using this color

Fonts for this mood

#040d8b reads as cool, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #040d8b
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 #040d8b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/040d8b-9e9cc4-df8f4e-241f2d-e9eef1?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