Color

#309bf3

#309bf3
hex#309bf3
rgbrgb(48, 155, 243)
hslhsl(207, 89%, 57%)
oklchoklch(0.672 0.161 248.3)
Closest name: Fresh Blue of Bel Air (#069af3)Relative luminance 0.3054

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#f38830

#30f3e9 · #303af3

#f3309b · #9bf330

Split-complementary

Open in tool →

#f3303a · #f3e930

#e930f3 · #f38830 · #3af330

Contrast

#309bf3 as textRatioAAAA largeAAAFix
Aaon white
2.95:1failfailfail
  • AA: use #0c77cf as the text (4.61:1)
  • AAA: use #09599a as the text (7.22:1)
  • AA: or shift the background to #2e2e2e (4.6:1)
  • AAA: or shift the background to #000000 (7.11:1)
Aaon black
7.11:1passpasspassPasses AAA — no fix needed.

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #309bf3 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

#309bf3 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #309bf3
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — generate_palette, check_contrast, analyze_color — read-only, no key. Every palette it proposes comes with a /palettes/new/… link: open it, lock what you like, paste the link back.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #309bf3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/309bf3-9cadc4-df4e53-1f212d-e9f1f1?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