Color

#183a3e

#183a3e
hex#183a3e
rgbrgb(24, 58, 62)
hslhsl(186, 44%, 17%)
oklchoklch(0.325 0.04 205.6)
Closest name: Royal Neptune (#1c3b42)Relative luminance 0.0357

Colors that go with #183a3e

Rust, Sienna and Steel 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 →

#3e1c18

#183e2f · #18283e

#3e183b · #3b3e18

Split-complementary

Open in tool →

#3e1828 · #3e2f18

#2f183e · #3e1c18 · #283e18

Contrast

#183a3e as textRatioAAAA largeAAAFix
Aaon white
12.25:1passpasspassPasses AAA — no fix needed.
Aaon black
1.71:1failfailfail
  • AA: use #358088 as the text (4.59:1)
  • AAA: use #43a2ad as the text (7.01:1)
  • AA: or shift the background to #9e9e9e (4.57:1)
  • AAA: or shift the background to #c4c4c4 (7.03:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #183a3e as the background.

Brands using this color

Fonts for this mood

#183a3e reads as cool, dark, luxury. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #183a3e
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 #183a3e and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/183a3e-a2b8be-df4e86-1f262d-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