Color

#309fbb

#309fbb
hex#309fbb
rgbrgb(48, 159, 187)
hslhsl(192, 59%, 46%)
oklchoklch(0.653 0.104 218.7)
Closest name: Blue Ocean (#009dc4)Relative luminance 0.2901

Colors that go with #309fbb

Charcoal, Orange Red 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 →

#bb4c30

#30bb91 · #305abb

#bb309f · #9fbb30

Split-complementary

Open in tool →

#bb305a · #bb9130

#9130bb · #bb4c30 · #5abb30

Contrast

#309fbb as textRatioAAAA largeAAAFix
Aaon white
3.09:1failpassfail
  • AA: use #278096 as the text (4.55:1)
  • AAA: use #1c5d6d as the text (7.4:1)
  • AA: or shift the background to #2b2b2b (4.59:1)
Aaon black
6.8:1passpassfail
  • AAA: use #31a2bf as the text (7.05:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #309fbb 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

#309fbb reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #309fbb
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 #309fbb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/309fbb-a2b5be-df4e77-1f242d-e9f1ef?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