Color

#3721ca

#3721ca
hex#3721ca
rgbrgb(55, 33, 202)
hslhsl(248, 72%, 46%)
oklchoklch(0.421 0.237 275)
Closest name: Busty Blue (#3300cc)Relative luminance 0.0616

Colors that go with #3721ca

Charcoal, Steel Blue and Cornflower 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 →

#b3ca21

#215fca · #8c21ca

#ca3721 · #21ca37

Split-complementary

Open in tool →

#ca8c21 · #5fca21

#ca215f · #b3ca21 · #21ca8c

Contrast

#3721ca as textRatioAAAA largeAAAFix
Aaon white
9.41:1passpasspassPasses AAA — no fix needed.
Aaon black
2.23:1failfailfail
  • AA: use #7361e5 as the text (4.57:1)
  • AAA: use #9689ec as the text (7.09:1)
  • AA: or shift the background to #b5b5b5 (4.59:1)
  • AAA: or shift the background to #e0e0e0 (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 #3721ca 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

#3721ca reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3721ca
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 #3721ca and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3721ca-a69cc4-dfac4e-271f2d-e9ecf1?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