Color

#373bb9

#373bb9
hex#373bb9
rgbrgb(55, 59, 185)
hslhsl(238, 54%, 47%)
oklchoklch(0.437 0.193 273.6)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0744

Colors that go with #373bb9

Charcoal, Sea Green 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 →

#b9b437

#377cb9 · #7437b9

#b9373b · #3bb937

Split-complementary

Open in tool →

#b97437 · #7cb937

#b9377c · #b9b437 · #37b974

Contrast

#373bb9 as textRatioAAAA largeAAAFix
Aaon white
8.44:1passpasspassPasses AAA — no fix needed.
Aaon black
2.49:1failfailfail
  • AA: use #6669d1 as the text (4.51:1)
  • AAA: use #8d90dd as the text (7.17:1)
  • AA: or shift the background to #bfbfbf (4.59:1)
  • AAA: or shift the background to #ebebeb (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 #373bb9 as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

Fonts for this mood

#373bb9 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #373bb9
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 #373bb9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/373bb9-9f9cc4-df944e-251f2d-e9edf1?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