Color

#03409b

#03409b
hex#03409b
rgbrgb(3, 64, 155)
hslhsl(216, 96%, 31%)
oklchoklch(0.4 0.159 260)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0605

Colors that go with #03409b

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 →

#9b5e03

#038c9b · #12039b

#9b0340 · #409b03

Split-complementary

Open in tool →

#9b1203 · #8c9b03

#9b038c · #9b5e03 · #039b12

Contrast

#03409b as textRatioAAAA largeAAAFix
Aaon white
9.5:1passpasspassPasses AAA — no fix needed.
Aaon black
2.21:1failfailfail
  • AA: use #0f6dfa as the text (4.59:1)
  • AAA: use #5095fb as the text (7.03:1)
  • AA: or shift the background to #b3b3b3 (4.53:1)
  • AAA: or shift the background to #dedede (7.06:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #03409b as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#03409b reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #03409b
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 #03409b and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/03409b-9ca7c4-df5f4e-201f2d-e9f0f1?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