Color

#373fb3

#373fb3
hex#373fb3
rgbrgb(55, 63, 179)
hslhsl(236, 53%, 46%)
oklchoklch(0.438 0.181 273.2)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.0762

Colors that go with #373fb3

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 →

#b3ab37

#377eb3 · #6d37b3

#b3373f · #3fb337

Split-complementary

Open in tool →

#b36d37 · #7eb337

#b3377e · #b3ab37 · #37b36d

Contrast

#373fb3 as textRatioAAAA largeAAAFix
Aaon white
8.32:1passpasspassPasses AAA — no fix needed.
Aaon black
2.52:1failfailfail
  • AA: use #676ed0 as the text (4.72:1)
  • AAA: use #8a8fdb as the text (7.03:1)
  • AA: or shift the background to #bfbfbf (4.52:1)
  • AAA: or shift the background to #ededed (7.11:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #373fb3 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

#373fb3 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #373fb3
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 #373fb3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/373fb3-9e9cc4-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