NEUTRALS

Underground

#665A51

RGB 102, 90, 81 · HSL 26°, 11%, 36% · CMYK 0, 12, 21, 60

Underground is #665A51 in HEX — rgb(102, 90, 81), hsl(26°, 11%, 36%), cmyk(0%, 12%, 21%, 60%).

Underground pulls into the rich end of the neutrals spectrum — HSL 26°, 11%, 36%. The neutral saturation makes it near-neutral and forgiving, and the hue reads cool. In interior projects it shines on main walls, trims, ceilings — versatile across nearly any style. Reads best alongside soft whites, natural wood, matte black trim, linen.

Color Codes

HEX#665A51

RGB102, 90, 81

HSL26°, 11%, 36%

HSV26°, 21%, 40%

CMYK0, 12, 21, 60

Decimal6707793

CSS RGBrgb(102, 90, 81)

CSS HSLhsl(26, 11%, 36%)

Paint Matches — this color across 16 brands

IKEA

IKEA138 138

ΔE 1 · #645850

Behr

Museum MQ2-44

ΔE 1.1 · #685A52

PPG

Intrigue 1019-7

ΔE 1.2 · #635951

Valspar

Italian Leather 6005-2C

ΔE 1.5 · #635A52

Dulux

Boycott S15A7

ΔE 1.9 · #635B53

Hallman-Lindsay

Wildwood 214

ΔE 2.2 · #60554C

Vista Paint

Rawhide C-1457

ΔE 2.3 · #61554E

Sherwin-Williams

Manor House SW7505

ΔE 2.6 · #665D57

Benjamin Moore

Middlebury HC-68

ΔE 2.7 · #6A5A4E

Kilz

Muddy Paws LL120

ΔE 3.4 · #6B625A

Dunn-Edwards

Missing Link DE6041

ΔE 3.7 · #6F5D57

RAL

Pearl Beige 1035

ΔE 4.4 · #6A5D4D

Farrow & Ball

Salon Drab 290

ΔE 5.9 · #726454

Colorhouse

Clay .06 Clay-06

ΔE 6.1 · #675544

Dutch Boy

Ashton Grey VS-9303

ΔE 6.7 · #66665A

Kobra

Brown 43

ΔE 8.5 · #624A3E

Light Reflectance & Undertone

Light Reflectance Value (LRV)

11/100

Dark

0 · DarkLight · 100

Soaks up light and feels moody and intimate. Great for studies, dining rooms and accent walls; pair with ample lighting.

Undertone

TemperatureWarm MasstoneOrange UndertoneYellow

A near-neutral with a subtle warm yellow undertone — it will pick up colour from surrounding surfaces and shift noticeably under different light.

Color Theory

Complementary

#665A51

#525D66

Analogous

#665253

#665A51

#666552

Triadic

#665A51

#52665A

#5A5266

Split-Complementary

#665A51

#526665

#525366

Tetradic

#665A51

#536652

#525D66

#655266

Monochromatic

#110F0E

#3B3530

#665A51

#908074

#B2A79F

Rectangle

#665A51

#5D6652

#525D66

#5A5266

Compound

#665A51

#666552

#525D66

#525366

Variations

Lighter

#8A7B6F

#A69C94

#CAC5C1

Darker

#524841

#39322C

#211D1A

Saturation

#5F5B59

#665A52

#8F5529

Interior Use

Best Rooms

living rooms, bedrooms, kitchens

Best Uses

main walls, trim, accents

Pairs With

soft whites, natural wood, brass, matte black trim

Accessibility (WCAG)

vs White

6.67:1

vs Black

3.15:1

AA Large

Deuteranopia

#665A51

#615E51

Original → Simulated

Protanopia

#665A51

#5C5C52

Original → Simulated

Tritanopia

#665A51

#66595A

Original → Simulated

Color Psychology

Quiet · Versatile

Underground gets out of the way so the architecture and the people in the room do the work. The right neutral is never a default — it reads warm or cool, dusty or sharp depending on its undertone, and that undertone is what makes or breaks the room.

SymbolismBalance, sophistication, calm

PersonalityAdaptable, considered, timeless

versatileneutraltimelessbackdroptrimwall

How it looks under different light

#8C7058

Warm Bulb 2700K

Incandescent / soft white LED — pulls colour toward yellow/amber.

#665A51

Daylight 5500K

Midday natural light or daylight-spec LED — closest to the paint chip.

#79757C

Cool Bulb 6500K

Cool white LED / overcast daylight — pulls colour toward blue.

Pairs With

#EBEBEA

Trim

Matched off-white

Same hue at 92% lightness — trim reads coordinated, not stark.

#F7F7F7

Ceiling

Whisper tint

Near-white with a hint of the hero's undertone — ceiling feels intentional.

#3B5162

Accent

Complementary punch

Hue +180°, slightly muted for paint vs. screen — use on a door, frame, or single piece.

#574738

Floor

Walnut neutral

Warm mid-brown grounds the scheme regardless of hero hue.

Paint Info

Brand · Product Line

Benjamin Moore / Regal Select Interior

Recommended Finishes

Eggshell (walls) · Pearl (trim) · Matte (ceiling)

Eggshell hides imperfections on main walls while keeping the color rich; pearl on trim adds subtle sheen and easier cleaning; flat matte on ceilings prevents glare.

Best Surfaces

Primary walls · Cabinetry · Doors · Mouldings

Coverage & Dry Time

Typical coverage 350-400 sq ft per gallon over a primed surface.

Touch-dry in ~1 hour. Recoat after 4 hours. Full cure 7-14 days.

Primer

Standard primer is adequate.

Application Tip

Use a 9" microfiber roller on walls and a 2.5" angled sash brush for trim cuts. Two coats minimum for even depth.

Paint Calculator

Wall area (m²)

Coats

Coverage (m² / L)

You'll need

4.0 litres

1.06 US gallons · room for one touch-up coat. Buy slightly more to ensure single-batch match.

Code Snippets

CSS — color

color: #665A51;

CSS — background

background-color: #665A51;

CSS Variable

--color-underground: #665A51;

Tailwind v3 — config

colors: { 'underground': '#665A51' }

Tailwind — arbitrary

bg-[#665A51] text-[#665A51]

SCSS

$underground: #665A51;

Similar Colors

Spanish Moss

#675D53 · ΔE 1.5

Middlebury Brown

#69594D · ΔE 2.7

Clinton Brown

#65554A · ΔE 2.9

Stone Brown

#5F544E · ΔE 3.1

Topeka Taupe

#60544F · ΔE 3.4

Dixon Brown

#695A4C · ΔE 3.4

Wood Grain Brown

#68554D · ΔE 3.6

Mustang

#68574A · ΔE 3.6

Built by DSGN.HOUSE Updated 2026

Our color tools run on our own catalogue of 26,000+ real paint colors across 16 brands — Benjamin Moore, Sherwin-Williams, Behr, Dulux, RAL and more — with the color math (HSL and CIELAB matching) computed in-house, not scraped from summaries. Every color you pick maps to a real, buyable paint with its code, so what you see here you can actually take to the store. We review and update these tools and their data regularly.

Created by Denis Kataev, founder of DSGN.HOUSE — a software engineer and digital entrepreneur building professional color-design tools for everyone.

Frequently Asked Questions

What color is #665A51?

#665A51 is Underground, a deep neutral with a cool undertone.

Is #665A51 warm or cool?

Underground reads cool, which influences how it interacts with surrounding tones and natural light.

What rooms work best with Underground?

Underground works well in living rooms, bedrooms, kitchens. Designers typically use it for main walls, trim, accents.

What colors pair well with Underground?

Underground pairs naturally with soft whites, natural wood, brass, matte black trim. Its complementary color is also a strong contrast option for accents.

Where can I download Underground?

You can download Underground on DSGN.HOUSE in 15 designer formats including CSS gradient, Figma, Procreate swatches, Tailwind config, Adobe ASE, SVG, and 4K wallpapers — all free.

What's the hex code for Underground?

The hex code is #665A51. In RGB it's 102, 90, 81, and in HSL it's 26°, 11%, 36%.

← All colors