Color

#21b3ba

#21b3ba
hex#21b3ba
rgbrgb(33, 179, 186)
hslhsl(183, 70%, 43%)
oklchoklch(0.7 0.113 200.1)
Closest name: lightseagreen (#20b2aa)Relative luminance 0.3611

Colors that go with #21b3ba

Charcoal, Denim and Dodger 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 →

#ba2921

#21ba75 · #2166ba

#ba21b3 · #b3ba21

Split-complementary

Open in tool →

#ba2166 · #ba7521

#7521ba · #ba2921 · #66ba21

Contrast

#21b3ba as textRatioAAAA largeAAAFix
Aaon white
2.55:1failfailfail
  • AA: use #188186 as the text (4.64:1)
  • AAA: use #126064 as the text (7.28:1)
  • AA: or shift the background to #383838 (4.59:1)
  • AAA: or shift the background to #171717 (7.02:1)
Aaon black
8.22:1passpasspassPasses 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 #21b3ba as the background.

Brands using this color

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

Fonts for this mood

#21b3ba reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #21b3ba
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 #21b3ba and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/21b3ba-a2b9be-d4598e-1f262d-e9f1ee?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