BLUES

Windows Blue

#3778BF

RGB 55, 120, 191 · HSL 211°, 55%, 48% · CMYK 71, 37, 0, 25

Windows Blue is #3778BF in HEX — rgb(55, 120, 191), hsl(211°, 55%, 48%), cmyk(71%, 37%, 0%, 25%).

Windows Blue pulls into the mid-tone end of the blues spectrum — HSL 211°, 55%, 48%. The balanced saturation makes it confident without overpowering, and the hue reads cool. In interior projects it shines on bedrooms, bathrooms, home offices — for calm, focused environments. Reads best alongside warm white trim, oak or walnut, brass or matte black hardware.

Color Codes

HEX#3778BF

RGB55, 120, 191

HSL211°, 55%, 48%

HSV211°, 71%, 75%

CMYK71, 37, 0, 25

Decimal3635391

CSS RGBrgb(55, 120, 191)

CSS HSLhsl(211, 55%, 48%)

Paint Matches — this color across 16 brands

PPG

Royal Plume 1243-6

ΔE 1.1 · #3C7AC2

Vista Paint

Soothing Sapphire K-129

ΔE 3 · #297BC1

Hallman-Lindsay

Parkwater 612

ΔE 3.7 · #477BBD

Behr

Liberty 580D-6

ΔE 3.7 · #407DBF

RAL

Sky Blue 5015

ΔE 4.6 · #2271B3

Dunn-Edwards

Beautiful Blue DEA136

ΔE 5 · #186DB6

Dulux

Mykonos S39H6

ΔE 5.4 · #387EBE

IKEA

IKEA128 128

ΔE 6.5 · #4A72B0

Valspar

Peek-A-Boo Blue 4007-10C

ΔE 7 · #3370AC

Benjamin Moore

Big 2066-30

ΔE 7.7 · #0167B2

Kilz

Aspiration RH190

ΔE 9.6 · #217AB4

Dutch Boy

Blue Sea VS-9451

ΔE 10.6 · #2D61AD

Sherwin-Williams

Blue Chip SW6959

ΔE 10.9 · #016EA7

Kobra

Blue 29

ΔE 16.2 · #1882B4

Colorhouse

Petal .05 Petal-05

ΔE 20 · #1F4992

Farrow & Ball

Cook's Blue 237

ΔE 23.1 · #6A90B4

Light Reflectance & Undertone

Light Reflectance Value (LRV)

18/100

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

TemperatureCool MasstoneBlue UndertoneViolet

Reads as a cool blue with a violet undertone showing through, especially in daylight. Pair trim and adjacent colours to either calm or amplify that undertone.

Color Theory

Complementary

#3778BF

#BE7D37

Analogous

#37BBBE

#3778BF

#3937BE

Triadic

#3778BF

#BE3778

#78BE37

Split-Complementary

#3778BF

#BE3937

#BBBE37

Tetradic

#3778BF

#BE37BB

#BE7D37

#37BE39

Monochromatic

#152D47

#265382

#3778BF

#6D9FD5

#A8C6E6

Rectangle

#3778BF

#7D37BE

#BE7D37

#78BE37

Compound

#3778BF

#3937BE

#BE7D37

#BBBE37

Variations

Lighter

#5B93CF

#8AAED5

#BFD0E2

Darker

#29609A

#1B426C

#0E2640

Saturation

#667A8F

#3778BE

#1C77D9

Interior Use

Best Rooms

bedrooms, bathrooms, home offices

Best Uses

main walls, ceilings, trim, cabinetry

Pairs With

warm white trim, oak or walnut, brass or matte black hardware

Accessibility (WCAG)

vs White

4.56:1

vs Black

4.60:1

Deuteranopia

#3778BF

#4D72C0

Original → Simulated

Protanopia

#3778BF

#7070B8

Original → Simulated

Tritanopia

#3778BF

#22867B

Original → Simulated

Color Psychology

Focused · Cooling

Windows Blue lowers the temperature of a room — useful in south-facing rooms that overheat visually, and in home offices where you want a clear head. Pair with warm wood and brass to keep it from reading clinical.

SymbolismTrust, depth, stability

PersonalityClear-headed, dependable, contemplative

focustrustcalmofficebedroomdepth

How it looks under different light

#6987AA

Warm Bulb 2700K

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

#3778BF

Daylight 5500K

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

#568CCF

Cool Bulb 6500K

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

Pairs With

#E9EBED

Trim

Matched off-white

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

#F7F7F8

Ceiling

Whisper tint

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

#996A37

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: #3778BF;

CSS — background

background-color: #3778BF;

CSS Variable

--color-windows-blue: #3778BF;

Tailwind v3 — config

colors: { 'windows-blue': '#3778BF' }

Tailwind — arbitrary

bg-[#3778BF] text-[#3778BF]

SCSS

$windows-blue: #3778BF;

Similar Colors

Big Country Blue

#0066B1 · ΔE 8.1

Paddington Blue

#1369A7 · ΔE 8.4

Athens Blue

#3D74AC · ΔE 8.8

Brilliant Blue

#0063A6 · ΔE 8.9

Mosaic

#3862A3 · ΔE 9.5

Waterdrop

#5C79B3 · ΔE 9.8

Watertown

#5B7EB7 · ΔE 9.9

Blue Lapis

#6289C6 · ΔE 10.3

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 #3778BF?

#3778BF is Windows Blue, a mid-tone blue with a cool undertone.

Is #3778BF warm or cool?

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

What rooms work best with Windows Blue?

Windows Blue works well in bedrooms, bathrooms, home offices. Designers typically use it for main walls, ceilings, trim, cabinetry.

What colors pair well with Windows Blue?

Windows Blue pairs naturally with warm white trim, oak or walnut, brass or matte black hardware. Its complementary color is also a strong contrast option for accents.

Where can I download Windows Blue?

You can download Windows Blue 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 Windows Blue?

The hex code is #3778BF. In RGB it's 55, 120, 191, and in HSL it's 211°, 55%, 48%.

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