Color

#5121ab

#5121ab
hex#5121ab
rgbrgb(81, 33, 171)
hslhsl(261, 68%, 40%)
oklchoklch(0.411 0.199 290.5)
Closest name: Intergalactic Settlement (#5b1e8b)Relative luminance 0.0578

Colors that go with #5121ab

Royal Blue, Midnight Blue and Olive 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 →

#7bab21

#2135ab · #9721ab

#ab5121 · #21ab51

Split-complementary

Open in tool →

#ab9721 · #35ab21

#ab2135 · #7bab21 · #21ab97

Contrast

#5121ab as textRatioAAAA largeAAAFix
Aaon white
9.74:1passpasspassPasses AAA — no fix needed.
Aaon black
2.16:1failfailfail
  • AA: use #8a5ce0 as the text (4.69:1)
  • AAA: use #a683e7 as the text (7.02:1)
  • AA: or shift the background to #b3b3b3 (4.65:1)
  • AAA: or shift the background to #dbdbdb (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 #5121ab 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

#5121ab reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #5121ab
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 #5121ab and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/5121ab-af9cc4-dfcb4e-2a1f2d-e9eaf1?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