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Slate Grey vs Sky Blue: What's the Difference?

The main difference between Slate Grey and Sky Blue is hue — Slate Grey is a cool blue, while Sky Blue is a cool cyan. Slate Grey (#708090) has an HSL of 210°, 13%, 50%, whereas Sky Blue (#87CEEB) sits at 197°, 71%, 73%.

Slate Grey#708090
Sky Blue#87CEEB
#708090Blended: #7CA7BE#87CEEB
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Slate Grey vs Sky Blue: Key Differences at a Glance

Aspect Slate Grey Sky Blue
BrightnessMedium (L=50%) — balanced, versatileLight (L=73%) — airy, soft, approachable
SaturationNear-neutral (S=13%) — desaturated and restrainedVivid (S=71%) — bright, energetic, eye-catching
Hue familyBlueCyan
TemperatureCoolCool
Hex code#708090#87CEEB
RGB112, 128, 144135, 206, 235

Can you use Slate Grey and Sky Blue together?

Sky Blue text on Slate Grey
Slate Grey text on Sky Blue
Contrast Ratio:2.33:1Insufficient Contrast

How to Tell Slate Grey and Sky Blue Apart

  • ●Look at lightness first: Sky Blue is noticeably lighter.
  • ●Check saturation: Sky Blue looks more vivid and saturated.
  • ●Watch the undertone: the hue shifts 13° between them, which changes the perceived temperature.
  • ●Compare them on a white background to see true saturation, and on black to see true lightness.

Slate Grey or Sky Blue: Which to Use and Where

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

◆Branding & logos
PickSky Blue

Sky Blue is more saturated (71% HSL vs 13%) so it reads as bolder and more memorable at logo scale, while Slate Grey can feel washed out when printed small.

▢Web UI & body text backgrounds
PickSlate Grey

Slate Grey hits a 4.05:1 WCAG contrast against white — safer for text-heavy interfaces — where Sky Blue only reaches 1.74:1 and risks failing AA at small body sizes.

⬡Fashion & apparel
PickSky Blue

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

▣Interior design & walls
PickSlate Grey

Slate Grey is the more muted of the two (13% saturation) and sits more calmly on large wall surfaces, while Sky Blue's higher chroma can overwhelm a room when used beyond accent pieces.

When to Use Slate Grey vs Sky Blue in Design

Use Slate Grey for:
●Tech and corporate trust
●Finance and banking brands
●Links and primary buttons
●Medical and professional UI
●Calm dependable visuals
Use Sky Blue for:
●Cool, techy, digital branding
●Water, ice, cleaning products
●Fresh modern UI accents
●Summer and tropical themes
●Youthful playful design

Slate Grey and Sky Blue Hex Codes, RGB & HSL

Slate Grey#708090

Slate Grey (#708090) is a medium, near-neutral blue with a cool undertone — it feels balanced, versatile and desaturated and restrained.

HEX
RGB
HSL
HSV
CMYK
PANTONE
Shades
Tints
Sky Blue#87CEEB

Sky Blue (#87CEEB) is a light, vivid cyan with a cool undertone — it feels airy, soft, approachable and bright, energetic, eye-catching.

HEX
RGB
HSL
HSV
CMYK
PANTONE
Shades
Tints

Slate Grey and Sky 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
Slate Grey text on white
4.05:1AA Large
Sample text preview
Slate Grey text on black
5.18:1AA
Sample text preview
Sky Blue text on white
1.74:1Fail
Sample text preview
Sky Blue text on black
12.06:1AAA
Sample text preview
Slate Grey text on Sky Blue
2.33:1Fail
Sample text preview
Sky Blue text on Slate Grey
2.33:1Fail

Explore Slate Grey and Sky Blue individually

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

Slate Grey color page#708090 · shades, tints, pairingsSky Blue color page#87CEEB · shades, tints, pairings

More Slate Grey and Sky Blue Comparisons

Slate GreyvsPewterSky BluevsGoldCharcoalvsSlate GreyAzurevsSky BlueSlate GreyvsGunmetalSky BluevsAzureSky BluevsCoralBaby BluevsSlate GreySky BluevsWhiteNavy BluevsSlate GreySky BluevsCeruleanSlate GrayvsSlate Grey

Slate Grey vs Sky Blue FAQ

What is the difference between slate grey and sky blue?+
The main difference between Slate Grey and Sky Blue is hue — Slate Grey is a cool blue, while Sky Blue is a cool cyan. Slate Grey (#708090) has an HSL of 210°, 13%, 50%, whereas Sky Blue (#87CEEB) sits at 197°, 71%, 73%.
Is slate grey darker than sky blue?+
Yes. Slate Grey is darker, with a lightness of 50% in HSL compared to Sky Blue at 73% — a 23-point gap.
Are slate grey and sky blue the same color?+
No. Slate Grey is #708090 and Sky Blue is #87CEEB. They differ by 13° in hue, 23% in lightness, and 58% in saturation.
Which is more saturated, slate grey or sky blue?+
Sky Blue is more saturated. In HSL, Slate Grey has 13% saturation and Sky Blue has 71% — Sky Blue is the more vivid of the two, while Slate Grey reads as more muted.
Is slate grey warm or cool?+
Slate Grey (#708090) is a cool blue. Its hue sits at 210° on the color wheel, which places it in the cool range.
Is sky blue warm or cool?+
Sky Blue (#87CEEB) is a cool cyan. Its hue sits at 197° on the color wheel, which places it in the cool range.
Can you use slate grey and sky blue together?+
Yes. Slate Grey (blue) and Sky Blue (cyan) 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 slate grey belong to?+
Slate Grey belongs to the blue family. Its HSL is 210°, 13%, 50% — a cool tone within the broader blue group.
What is the hex code for slate grey?+
The hex code for Slate Grey is #708090. In RGB, that's rgb(112, 128, 144), and in HSL it's hsl(210, 13%, 50%).
What is the hex code for sky blue?+
The hex code for Sky Blue is #87CEEB. In RGB, that's rgb(135, 206, 235), and in HSL it's hsl(197, 71%, 73%).