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Dark Blue vs Cobalt Blue: What's the Difference?

The main difference between Dark Blue and Cobalt Blue is hue — Dark Blue is a cool purple, while Cobalt Blue is a cool blue. Dark Blue (#00008B) has an HSL of 240°, 100%, 27%, whereas Cobalt Blue (#0047AB) sits at 215°, 100%, 34%.

Dark Blue#00008B
Cobalt Blue#0047AB
#00008BBlended: #00249B#0047AB
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Dark Blue vs Cobalt Blue: Key Differences at a Glance

Aspect Dark Blue Cobalt Blue
BrightnessDark (L=27%) — rich, serious, substantialDark (L=34%) — rich, serious, substantial
SaturationVivid (S=100%) — bright, energetic, eye-catchingVivid (S=100%) — bright, energetic, eye-catching
Hue familyPurpleBlue
TemperatureCoolCool
Hex code#00008B#0047AB
RGB0, 0, 1390, 71, 171

Can you use Dark Blue and Cobalt Blue together?

Cobalt Blue text on Dark Blue
Dark Blue text on Cobalt Blue
Contrast Ratio:1.81:1Insufficient Contrast

How to Tell Dark Blue and Cobalt Blue Apart

  • ●Watch the undertone: the hue shifts 25° between them, which changes the perceived temperature.
  • ●Compare them on a white background to see true saturation, and on black to see true lightness.

Dark Blue or Cobalt Blue: Which to Use and Where

Four real design scenarios, with the recommended pick based on hue, saturation, and WCAG contrast.

◆Branding & logos
PickDark Blue

Dark Blue is more saturated (100% HSL vs 100%) so it reads as bolder and more memorable at logo scale, while Cobalt Blue can feel washed out when printed small.

▢Web UI & body text backgrounds
PickDark Blue

Dark Blue hits a 15.30:1 WCAG contrast against white — safer for text-heavy interfaces — where Cobalt Blue only reaches 8.44:1 and risks failing AA at small body sizes.

⬡Fashion & apparel
PickCobalt Blue

Cobalt Blue is a cool-leaning tone that flatters spring/summer collections and warmer skin undertones, while Dark Blue leans cooler and is better suited to autumn/winter layering.

▣Interior design & walls
PickDark Blue

Dark Blue is the more muted of the two (100% saturation) and sits more calmly on large wall surfaces, while Cobalt Blue's higher chroma can overwhelm a room when used beyond accent pieces.

When to Use Dark Blue vs Cobalt Blue in Design

Use Dark Blue for:
●Luxury and premium brands
●Creative and imaginative themes
●Beauty and wellness
●Spiritual and mystical design
●Night and evening moods
Use Cobalt Blue for:
●Tech and corporate trust
●Finance and banking brands
●Links and primary buttons
●Medical and professional UI
●Calm dependable visuals

Dark Blue and Cobalt Blue Hex Codes, RGB & HSL

Dark Blue#00008B

Dark Blue (#00008B) is a dark, vivid purple with a cool undertone — it feels rich, serious, substantial and bright, energetic, eye-catching.

HEX
RGB
HSL
HSV
CMYK
PANTONE
Shades
Tints
Cobalt Blue#0047AB

Cobalt Blue (#0047AB) is a dark, vivid blue with a cool undertone — it feels rich, serious, substantial and bright, energetic, eye-catching.

HEX
RGB
HSL
HSV
CMYK
PANTONE
Shades
Tints

Dark Blue and Cobalt Blue WCAG Contrast Ratios

Text legibility depends on the contrast ratio between foreground and background. WCAG 2.1 AA requires at least 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Use these numbers to choose accessible combinations for your design.

Sample text preview
Dark Blue text on white
15.3:1AAA
Sample text preview
Dark Blue text on black
1.37:1Fail
Sample text preview
Cobalt Blue text on white
8.44:1AAA
Sample text preview
Cobalt Blue text on black
2.49:1Fail
Sample text preview
Dark Blue text on Cobalt Blue
1.81:1Fail
Sample text preview
Cobalt Blue text on Dark Blue
1.81:1Fail

Explore Dark Blue and Cobalt Blue individually

Each color has a dedicated page with shades, tints, CSS name, pairings, and color psychology.

Cobalt Blue color page#0047AB · shades, tints, pairings

More Dark Blue and Cobalt Blue Comparisons

NavyvsCobalt BlueCobalt BluevsCeruleanCharcoalvsCobalt BlueCobalt BluevsSky BlueCobalt BluevsGunmetalNavy BluevsCobalt BlueBaby BluevsCobalt BlueRoyal BluevsCobalt BlueCobalt BluevsCornflowerCobalt BluevsSlate Grey

Dark Blue vs Cobalt Blue FAQ

What is the difference between dark blue and cobalt blue?+
The main difference between Dark Blue and Cobalt Blue is hue — Dark Blue is a cool purple, while Cobalt Blue is a cool blue. Dark Blue (#00008B) has an HSL of 240°, 100%, 27%, whereas Cobalt Blue (#0047AB) sits at 215°, 100%, 34%.
Is dark blue darker than cobalt blue?+
Yes. Dark Blue is darker, with a lightness of 27% in HSL compared to Cobalt Blue at 34% — a 7-point gap.
Are dark blue and cobalt blue the same color?+
No. Dark Blue is #00008B and Cobalt Blue is #0047AB. They differ by 25° in hue, 7% in lightness, and 0% in saturation.
Which is more saturated, dark blue or cobalt blue?+
They have nearly identical saturation — Dark Blue at 100% and Cobalt Blue at 100% in HSL.
Is dark blue warm or cool?+
Dark Blue (#00008B) is a cool purple. Its hue sits at 240° on the color wheel, which places it in the cool range.
Is cobalt blue warm or cool?+
Cobalt Blue (#0047AB) is a cool blue. Its hue sits at 215° on the color wheel, which places it in the cool range.
Can you use dark blue and cobalt blue together?+
Yes. Dark Blue (purple) and Cobalt Blue (blue) can work as a complementary or analogous pair. Use one as the dominant tone and the other as a 10–20% accent to keep the palette balanced.
What color family does dark blue belong to?+
Dark Blue belongs to the purple family. Its HSL is 240°, 100%, 27% — a cool tone within the broader purple group.
What is the hex code for dark blue?+
The hex code for Dark Blue is #00008B. In RGB, that's rgb(0, 0, 139), and in HSL it's hsl(240, 100%, 27%).
What is the hex code for cobalt blue?+
The hex code for Cobalt Blue is #0047AB. In RGB, that's rgb(0, 71, 171), and in HSL it's hsl(215, 100%, 34%).