Color

#3e51bb

#3e51bb
hex#3e51bb
rgbrgb(62, 81, 187)
hslhsl(231, 50%, 49%)
oklchoklch(0.482 0.167 271.1)
Closest name: Blasphemous Blue (#3356aa)Relative luminance 0.105

Colors that go with #3e51bb

Charcoal, Sea Green and Amber 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 →

#bba93e

#3e90bb · #6a3ebb

#bb3e51 · #51bb3e

Split-complementary

Open in tool →

#bb6a3e · #90bb3e

#bb3e90 · #bba93e · #3ebb6a

Contrast

#3e51bb as textRatioAAAA largeAAAFix
Aaon white
6.78:1passpassfail
  • AAA: use #3c4eb4 as the text (7.14:1)
Aaon black
3.1:1failpassfail
  • AA: use #5e6ec9 as the text (4.55:1)
  • AAA: use #8591d6 as the text (7.02:1)
  • AA: or shift the background to #d4d4d4 (4.57:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3e51bb as the background.

Brands using this color

Fonts for this mood

#3e51bb reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3e51bb
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 #3e51bb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3e51bb-9c9ec4-df834e-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