Color

#21b58e

#21b58e
hex#21b58e
rgbrgb(33, 181, 142)
hslhsl(164, 69%, 42%)
oklchoklch(0.691 0.131 169.4)
Closest name: Hobgoblin (#01ad8f)Relative luminance 0.3532

Colors that go with #21b58e

Charcoal, Hot Pink and 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 →

#b52149

#21b544 · #2193b5

#8e21b5 · #b58e21

Split-complementary

Open in tool →

#b52193 · #b54421

#4421b5 · #b52149 · #93b521

Contrast

#21b58e as textRatioAAAA largeAAAFix
Aaon white
2.6:1failfailfail
  • AA: use #198669 as the text (4.51:1)
  • AAA: use #12634e as the text (7.19:1)
  • AA: or shift the background to #383838 (4.5:1)
  • AAA: or shift the background to #141414 (7.07:1)
Aaon black
8.06:1passpasspassPasses 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 #21b58e as the background.

Brands using this color

mcpConnect your agent — build around #21b58e
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 #21b58e and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/21b58e-a2beba-d459b5-1f2b2d-e9f1eb?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