Color

#303ea6

#303ea6
hex#303ea6
rgbrgb(48, 62, 166)
hslhsl(233, 55%, 42%)
oklchoklch(0.421 0.166 271.3)
Closest name: Bluebell (#333399)Relative luminance 0.0683

Colors that go with #303ea6

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.

Real palettes that use #303ea6

Tints & shades

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

Harmonies

Complementary

Open in tool →

#a69830

#3079a6 · #5d30a6

#a6303e · #3ea630

Split-complementary

Open in tool →

#a65d30 · #79a630

#a63079 · #a69830 · #30a65d

Contrast

#303ea6 as textRatioAAAA largeAAAFix
Aaon white
8.88:1passpasspassPasses AAA — no fix needed.
Aaon black
2.37:1failfailfail
  • AA: use #616ed1 as the text (4.66:1)
  • AAA: use #8892dd as the text (7.2:1)
  • AA: or shift the background to #bababa (4.57:1)
  • AAA: or shift the background to #e6e6e6 (7.11:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #303ea6 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

#303ea6 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #303ea6
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 #303ea6 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/303ea6-9c9cc4-df884e-241f2d-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