Color

#b40404

#b40404
hex#b40404
rgbrgb(180, 4, 4)
hslhsl(0, 96%, 36%)
oklchoklch(0.485 0.197 29)
Closest name: All Systems Red (#b30103)Relative luminance 0.098

Tints & shades

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

Harmonies

Complementary

Open in tool →

#04b4b4

#b4045c · #b45c04

#04b404 · #0404b4

Split-complementary

Open in tool →

#04b45c · #045cb4

#5cb404 · #04b4b4 · #5c04b4

Contrast

#b40404 as textRatioAAAA largeAAAFix
Aaon white
7.1:1passpasspassPasses AAA — no fix needed.
Aaon black
2.96:1failfailfail
  • AA: use #eb0505 as the text (4.56:1)
  • AAA: use #fc6464 as the text (7.15:1)
  • AA: or shift the background to #cfcfcf (4.55:1)
  • AAA: or shift the background to #ffffff (7.1:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #b40404 as the background.

Brands using this color

Fonts for this mood

#b40404 reads as warm, vivid, playful. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #b40404
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 #b40404 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/b40404-c4a19c-62cb98-2d251f-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