Color

#51a3f0

#51a3f0
hex#51a3f0
rgbrgb(81, 163, 240)
hslhsl(209, 84%, 63%)
oklchoklch(0.698 0.139 249.2)
Closest name: Cerulean (#55aaee)Relative luminance 0.3423

Tints & shades

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

Harmonies

Complementary

Open in tool →

#f09e51

#51f0ed · #5154f0

#f051a3 · #a3f051

Split-complementary

Open in tool →

#f05154 · #f0ed51

#ed51f0 · #f09e51 · #54f051

Contrast

#51a3f0 as textRatioAAAA largeAAAFix
Aaon white
2.68:1failfailfail
  • AA: use #1276d3 as the text (4.61:1)
  • AAA: use #0e59a0 as the text (7.11:1)
  • AA: or shift the background to #363636 (4.52:1)
  • AAA: or shift the background to #121212 (7:1)
Aaon black
7.85:1passpasspassPasses 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 #51a3f0 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

#51a3f0 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #51a3f0
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 #51a3f0 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/51a3f0-9cacc4-df4e4e-1f212d-e9f1f1?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