Color

#3fc421

#3fc421
hex#3fc421
rgbrgb(63, 196, 33)
hslhsl(109, 71%, 45%)
oklchoklch(0.72 0.223 140.8)
Closest name: Crude Banana (#21c40e)Relative luminance 0.4065

Tints & shades

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

Harmonies

Complementary

Open in tool →

#a621c4

#91c421 · #21c455

#213fc4 · #c4213f

Split-complementary

Open in tool →

#5521c4 · #c42191

#2191c4 · #a621c4 · #c45521

Contrast

#3fc421 as textRatioAAAA largeAAAFix
Aaon white
2.3:1failfailfail
  • AA: use #2c8717 as the text (4.58:1)
  • AAA: use #206411 as the text (7.26:1)
  • AA: or shift the background to #404040 (4.51:1)
  • AAA: or shift the background to #212121 (7:1)
Aaon black
9.13:1passpasspassPasses 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 #3fc421 as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

mcpConnect your agent — build around #3fc421
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 #3fc421 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3fc421-a4bea2-7e4edf-1f2d23-eef1e9?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