Color

#516df5

#516df5
hex#516df5
rgbrgb(81, 109, 245)
hslhsl(230, 89%, 64%)
oklchoklch(0.59 0.205 270.1)
Closest name: Blue Öyster Cult (#5577ee)Relative luminance 0.1928

Colors that go with #516df5

Charcoal, Crimson and Sea Green 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 →

#f5da51

#51bef5 · #8851f5

#f5516d · #6df551

Split-complementary

Open in tool →

#f58851 · #bef551

#f551be · #f5da51 · #51f588

Contrast

#516df5 as textRatioAAAA largeAAAFix
Aaon white
4.32:1failpassfail
  • AA: use #4d69f5 as the text (4.51:1)
  • AAA: use #183cf2 as the text (7.08:1)
  • AA: or shift the background to #0a0a0a (4.58:1)
Aaon black
4.86:1passpassfail
  • AAA: use #7d91f7 as the text (7.27:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #516df5 as the background.

Brands using this color

Fonts for this mood

#516df5 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #516df5
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 #516df5 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/516df5-9c9ec4-df814e-231f2d-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