Color

#183d58

#183d58
hex#183d58
rgbrgb(24, 61, 88)
hslhsl(205, 57%, 22%)
oklchoklch(0.347 0.063 243.2)
Closest name: Capital Blue (#1a4157)Relative luminance 0.0424

Colors that go with #183d58

Royal Blue, Teal and Sienna 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 →

#583318

#185853 · #181d58

#58183d · #3d5818

Split-complementary

Open in tool →

#58181d · #585318

#531858 · #583318 · #1d5818

Contrast

#183d58 as textRatioAAAA largeAAAFix
Aaon white
11.37:1passpasspassPasses AAA — no fix needed.
Aaon black
1.85:1failfailfail
  • AA: use #307bb0 as the text (4.59:1)
  • AAA: use #539cd0 as the text (7.03:1)
  • AA: or shift the background to #a3a3a3 (4.51:1)
  • AAA: or shift the background to #cccccc (7.08:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #183d58 as the background.

Brands using this color

Fonts for this mood

#183d58 reads as cool, dark, luxury. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #183d58
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 #183d58 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/183d58-9cafc4-df4e58-1f212d-e9f1f0?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