Color

#21c4bf

#21c4bf
hex#21c4bf
rgbrgb(33, 196, 191)
hslhsl(178, 71%, 45%)
oklchoklch(0.743 0.123 191.5)
Closest name: Emerald Bliss (#4cbdac)Relative luminance 0.4356

Colors that go with #21c4bf

Charcoal, Dodger Blue and Midnight 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 →

#c42127

#21c46d · #2178c4

#bf21c4 · #c4bf21

Split-complementary

Open in tool →

#c42178 · #c46d21

#6d21c4 · #c42127 · #78c421

Contrast

#21c4bf as textRatioAAAA largeAAAFix
Aaon white
2.16:1failfailfail
  • AA: use #16837f as the text (4.58:1)
  • AAA: use #10605d as the text (7.36:1)
  • AA: or shift the background to #424242 (4.65:1)
  • AAA: or shift the background to #242424 (7.18:1)
Aaon black
9.71:1passpasspassPasses 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 #21c4bf 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 #21c4bf
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 #21c4bf and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/21c4bf-a2bcbe-d45999-1f282d-e9f1ed?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