Color

#343fb7

#343fb7
hex#343fb7
rgbrgb(52, 63, 183)
hslhsl(235, 56%, 46%)
oklchoklch(0.44 0.187 272)
Closest name: Cobalt Blue (#0047ab)Relative luminance 0.077

Colors that go with #343fb7

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 →

#b7ac34

#3480b7 · #6a34b7

#b7343f · #3fb734

Split-complementary

Open in tool →

#b76a34 · #80b734

#b73480 · #b7ac34 · #34b76a

Contrast

#343fb7 as textRatioAAAA largeAAAFix
Aaon white
8.27:1passpasspassPasses AAA — no fix needed.
Aaon black
2.54:1failfailfail
  • AA: use #646dd3 as the text (4.67:1)
  • AAA: use #888fdd as the text (7.02:1)
  • AA: or shift the background to #c2c2c2 (4.64:1)
  • AAA: or shift the background to #ededed (7.06:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #343fb7 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

#343fb7 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #343fb7
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 #343fb7 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/343fb7-9e9cc4-df8d4e-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