Color

#3151b9

#3151b9
hex#3151b9
rgbrgb(49, 81, 185)
hslhsl(226, 58%, 46%)
oklchoklch(0.474 0.168 266.8)
Closest name: Blasphemous Blue (#3356aa)Relative luminance 0.1004

Colors that go with #3151b9

Charcoal, Sea Green and Steel 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 →

#b99a31

#3195b9 · #5631b9

#b93151 · #51b931

Split-complementary

Open in tool →

#b95631 · #95b931

#b93195 · #b99a31 · #31b956

Contrast

#3151b9 as textRatioAAAA largeAAAFix
Aaon white
6.98:1passpassfail
  • AAA: use #304fb5 as the text (7.21:1)
Aaon black
3.01:1failpassfail
  • AA: use #526fd1 as the text (4.55:1)
  • AAA: use #7e94dd as the text (7.17:1)
  • AA: or shift the background to #d1d1d1 (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 #3151b9 as the background.

Brands using this color

Fonts for this mood

#3151b9 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3151b9
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 #3151b9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3151b9-9ca1c4-df774e-221f2d-e9eff1?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