Color

#581bf3

#581bf3
hex#581bf3
rgbrgb(88, 27, 243)
hslhsl(257, 90%, 53%)
oklchoklch(0.488 0.276 281.8)
Closest name: Electric Indigo (#6600ff)Relative luminance 0.0933

Colors that go with #581bf3

Charcoal, Denim and Cobalt 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 →

#b6f31b

#1b4af3 · #c41bf3

#f3581b · #1bf358

Split-complementary

Open in tool →

#f3c41b · #4af31b

#f31b4a · #b6f31b · #1bf3c4

Contrast

#581bf3 as textRatioAAAA largeAAAFix
Aaon white
7.33:1passpasspassPasses AAA — no fix needed.
Aaon black
2.87:1failfailfail
  • AA: use #8355f6 as the text (4.6:1)
  • AAA: use #a381f8 as the text (7.05:1)
  • AA: or shift the background to #cccccc (4.56:1)
  • AAA: or shift the background to #fafafa (7.02:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #581bf3 as the background.

Brands using this color

Fonts for this mood

#581bf3 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #581bf3
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 #581bf3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/581bf3-ac9cc4-dfc24e-291f2d-e9ebf1?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