Color

#381bf3

#381bf3
hex#381bf3
rgbrgb(56, 27, 243)
hslhsl(248, 90%, 53%)
oklchoklch(0.465 0.283 272.3)
Closest name: Overdue Blue (#4400ff)Relative luminance 0.081

Colors that go with #381bf3

Charcoal, Cobalt 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 →

#d6f31b

#1b6af3 · #a41bf3

#f3381b · #1bf338

Split-complementary

Open in tool →

#f3a41b · #6af31b

#f31b6a · #d6f31b · #1bf3a4

Contrast

#381bf3 as textRatioAAAA largeAAAFix
Aaon white
8.02:1passpasspassPasses AAA — no fix needed.
Aaon black
2.62:1failfailfail
  • AA: use #735ff7 as the text (4.71:1)
  • AAA: use #9586f9 as the text (7.06:1)
  • AA: or shift the background to #c2c2c2 (4.5:1)
  • AAA: or shift the background to #f0f0f0 (7.04:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #381bf3 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

#381bf3 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #381bf3
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 #381bf3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/381bf3-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