Color

#b40407

#b40407
hex#b40407
rgbrgb(180, 4, 7)
hslhsl(359, 96%, 36%)
oklchoklch(0.485 0.197 28.7)
Closest name: All Systems Red (#b30103)Relative luminance 0.0981

Colors that go with #b40407

Royal Blue, Teal 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 →

#04b4b1

#b4045f · #b45904

#07b404 · #0407b4

Split-complementary

Open in tool →

#04b459 · #045fb4

#5fb404 · #04b4b1 · #5904b4

Contrast

#b40407 as textRatioAAAA largeAAAFix
Aaon white
7.09:1passpasspassPasses AAA — no fix needed.
Aaon black
2.96:1failfailfail
  • AA: use #eb0509 as the text (4.56:1)
  • AAA: use #fc6467 as the text (7.16:1)
  • AA: or shift the background to #cfcfcf (4.55:1)
  • AAA: or shift the background to #ffffff (7.09:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #b40407 as the background.

Brands using this color

Fonts for this mood

#b40407 reads as warm, vivid, playful. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #b40407
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 #b40407 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/b40407-c4a09c-62cb96-2d251f-f1e9ed?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