Cobalt Blue Hex Code — #0047AB

RGB, HSL, and CMYK values for Cobalt Blue.

Last updated: April 6, 2026

Cobalt Blue Color Values

Format	Value
HEX	#0047AB
RGB	rgb(0, 71, 171)
HSL	hsl(215, 100%, 34%)
CMYK	cmyk(100%, 58%, 0%, 33%)

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About Cobalt Blue

Color psychology: Trust, depth.

Cobalt Blue (#0047AB) is a dark shade of blue with a hue angle of 215° on the color wheel, 100% saturation, and 34% lightness. It's commonly used in web design, graphic design, and branding where trust, depth are desired associations.

In color theory, Cobalt Blue sits in the cool section of the spectrum. Its high saturation makes it vivid and attention-grabbing — ideal for CTAs, headings, and brand accents.

When to Use Cobalt Blue in Design

Web Design

Use Cobalt Blue for headings, links, or accent elements against light backgrounds. Dark colors like this provide strong contrast and draw the eye to important content.

Branding & Logo

Cobalt Blue conveys trust, depth — consider it for brands that want to project these qualities. Test it at small sizes (favicon, social avatar) to ensure it remains recognizable.

Print Design

Use the CMYK values (C:100% M:58% Y:0% K:33%) for accurate print reproduction in brochures, business cards, and packaging. Request a physical proof — screen colors often appear more vibrant than their printed equivalents.

UI / UX Design

Dark colors like Cobalt Blue are effective for primary buttons, navigation bars, and text. Use a lighter tint (increase HSL lightness to 90%+) for hover backgrounds.

How to Use Cobalt Blue in CSS

/* Using HEX */
color: #0047AB;
background-color: #0047AB;

/* Using RGB */
color: rgb(0, 71, 171);

/* Using HSL — best for creating variations */
color: hsl(215, 100%, 34%);

/* Transparent overlay (50% opacity) */
background-color: rgba(0, 71, 171, 0.5);

/* Lighter variant for hover states */
background-color: hsl(215, 100%, 44%);

/* Darker variant for active states */
background-color: hsl(215, 100%, 24%);

HSL is the most flexible format for creating color systems. By adjusting the lightness value, you can generate an entire shade scale from Cobalt Blue without changing its core hue or saturation.

Colors That Go With Cobalt Blue

Complementary

Analogous

Triadic

Similar Shades of Blue

Cobalt

#0047AB

Light Steel Blue

#B0C4DE

Sapphire

#0F52BA

Facebook Blue

#1877F2

Denim Blue

#1560BD

Cornflower Blue

#6495ED

Frequently Asked Questions

What is the hex code for Cobalt Blue?

The hex color code for Cobalt Blue is #0047AB. In CSS, apply it as text color with color: #0047AB;, as a background with background-color: #0047AB;, or as a border with border-color: #0047AB;. Hex is the most widely used color notation on the web because it is compact, supported by every browser, and easy to copy between design tools like Figma, Photoshop, and code editors.

What is Cobalt Blue in RGB and when should I use RGB?

Cobalt Blue in RGB is rgb(0, 71, 171), where Red=0, Green=71, and Blue=171 on a 0-255 scale. Use RGB when you need transparency — rgba(0, 71, 171, 0.5) creates a 50% transparent version. RGB is also the native format for HTML canvas, WebGL, and JavaScript image manipulation, since each channel represents the intensity of that primary light color on screen displays.

How to use Cobalt Blue in CSS with different color formats?

Cobalt Blue can be applied in CSS using multiple formats: (1) Hex: color: #0047AB; — most compact and widely used. (2) RGB: color: rgb(0, 71, 171); — useful when calculating colors dynamically in JavaScript. (3) HSL: color: hsl(215, 100%, 34%); — best for creating variations, since adjusting lightness produces lighter or darker shades while keeping the same hue. (4) With transparency: rgba(0, 71, 171, 0.8); or hsla(215, 100%, 34%, 0.8); for 80% opacity overlays.

What is the HSL value of Cobalt Blue and why is HSL useful for designers?

Cobalt Blue in HSL is hsl(215, 100%, 34%). HSL stands for Hue (215 degrees on the color wheel), Saturation (100% color intensity), and Lightness (34% brightness). HSL is the most intuitive format for designers because you can create harmonious palettes by rotating the hue, generate hover effects by increasing lightness by 10%, and desaturate colors by reducing the S value. This makes Cobalt Blue a dark, vivid cool-toned color.

What is the CMYK value of Cobalt Blue for print design?

Cobalt Blue in CMYK is C:100% M:58% Y:0% K:33%. CMYK (Cyan, Magenta, Yellow, Key/Black) is the standard color model for professional printing — business cards, brochures, merchandise, and packaging. When designing for print in Adobe InDesign or Illustrator, use these exact CMYK values to ensure accurate color reproduction. Screen colors (RGB) often appear more vibrant than their printed CMYK equivalents, so always request a physical proof for brand-critical materials.

What colors pair well with Cobalt Blue in design projects?

Blue is the most universally liked color and pairs with almost anything. Use light blue backgrounds with dark text for calm interfaces, or pair navy with white for a professional, trustworthy look.

Is Cobalt Blue (#0047AB) accessible for web design and WCAG compliant?

Blue-on-white is one of the safer combinations for color-blind users, but ensure the shade is dark enough (below #1565C0) for WCAG AA text compliance at the standard 4.5:1 ratio. For Cobalt Blue specifically: as a dark shade (lightness: 34%), it can work as a text color on light backgrounds, but verify the exact contrast ratio using a contrast checker tool. WCAG 2.1 requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text (18px+ bold or 24px+ regular).

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Written by

Tamanna Tasnim

Senior Full Stack Developer

ToolsContainerDhaka, Bangladesh5+ years experiencetasnim@toolscontainer.com www.toolscontainer.com

Full-stack developer with deep expertise in data formats, APIs, and developer tooling. Writes in-depth technical comparisons and conversion guides backed by hands-on engineering experience across modern web stacks.

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