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Aspect Ratio Calculator — Resize Images & Video

Find the perfect aspect ratio and resize images or video while keeping proportions

Aspect Ratio

16:9

Dimensions

1,920 × 1,080

Decimal

1.778

px
px

Aspect Ratios

Aspect Ratio

Simplified Ratio

16:9

Decimal

1.778

Megapixels

2.07 MP

Original Size1920 × 1080 px
Total Pixels2,073,600
OrientationLandscape

Visual Preview

16:9

Matching Platforms

YouTubeTwitter/XFacebook VideoTwitch

Common Resolutions (16:9)

HD (720p)1,280 × 720
Full HD (1080p)1,920 × 1,080
QHD (1440p)2,560 × 1,440
4K UHD3,840 × 2,160
8K UHD7,680 × 4,320

Dimension Comparison

Width1,920 px
Height1,080 px

Example Calculations

1Standard 1080p (Full HD)

Inputs

Width1920 px
Height1080 px

Result

Aspect Ratio16:9
Decimal1.778
Megapixels2.07 MP
OrientationLandscape

GCD(1920, 1080) = 120. Ratio = 1920/120 : 1080/120 = 16:9. Megapixels = 1920 × 1080 / 1,000,000 = 2.07 MP.

2Instagram Portrait Post

Inputs

Width1080 px
Height1350 px

Result

Aspect Ratio4:5
Decimal0.800
Megapixels1.46 MP
OrientationPortrait

GCD(1080, 1350) = 270. Ratio = 1080/270 : 1350/270 = 4:5. Megapixels = 1080 × 1350 / 1,000,000 = 1.46 MP.

3Resize 4K to 1280 Wide

Inputs

Width3840 px
Height2160 px
New Width1280 px

Result

Resized Dimensions1280 × 720 px
Aspect Ratio16:9
Original Megapixels8.29 MP

GCD(3840, 2160) = 120, ratio = 16:9. New height = 1280 × (9/16) = 720. The resized image is 1280×720 at 16:9.

Frequently Asked Questions

Q

What is an aspect ratio and how do I calculate it?

An aspect ratio is the proportional relationship between width and height, expressed as W:H. To calculate it, divide both dimensions by their greatest common divisor (GCD). For example, 1920×1080 has a GCD of 120, so the ratio is 16:9. Aspect ratios determine how content appears on different screens.

  • 1920 ÷ 120 = 16, 1080 ÷ 120 = 9, so 1920×1080 = 16:9
  • The GCD is found using the Euclidean algorithm — repeatedly divide and take remainders
  • A ratio of 1:1 means perfectly square (e.g., 1080×1080 for Instagram)
  • Decimal form: 16:9 = 1.778, 4:3 = 1.333, 1:1 = 1.000
  • Matching ratio is required when resizing to avoid distortion or cropping
DimensionsGCDAspect RatioDecimal
1920×108012016:91.778
1080×108010801:11.000
1080×13502704:50.800
1280×7208016:91.778
Q

What aspect ratio should I use for social media?

Each platform has preferred dimensions. Instagram Feed uses 1:1 (1080×1080) or 4:5 (1080×1350). TikTok, Reels, and Shorts use 9:16 (1080×1920). YouTube and Twitter/X use 16:9 (1920×1080). Pinterest prefers 2:3 (1000×1500). Using the wrong ratio leads to cropping or black bars.

  • Instagram Feed: 1:1 (1080×1080) or 4:5 portrait (1080×1350) for maximum screen area
  • TikTok / Reels / Shorts: 9:16 vertical (1080×1920) — full-screen portrait
  • YouTube: 16:9 (1920×1080 minimum, 2560×1440 for crisp playback)
  • Pinterest: 2:3 (1000×1500) for standard pins; longer pins get truncated in feeds
  • Twitter/X: 16:9 (1600×900) for posts; 3:1 (1500×500) for header banners
PlatformRatioRecommended Size
Instagram Feed1:1 or 4:51080×1080 / 1080×1350
TikTok / Reels9:161080×1920
YouTube16:91920×1080
Pinterest2:31000×1500
Twitter/X16:91600×900
Q

How do I resize an image without distortion?

To resize without distortion, maintain the original aspect ratio. Divide the new width by the original ratio to get the new height (or vice versa). For example, to resize 1920×1080 (16:9) to 1280px wide: 1280 × (9/16) = 720. The resized image is 1280×720, preserving the 16:9 ratio.

  • New Height = New Width × (Original Height / Original Width)
  • New Width = New Height × (Original Width / Original Height)
  • Example: 3840×2160 resized to 1920 wide → 1920 × (2160/3840) = 1080 → 1920×1080
  • Never stretch one dimension independently — this causes visible distortion
  • Most image editors have a "lock aspect ratio" or chain-link icon for this purpose
Q

What is the difference between 16:9 and 4:3 aspect ratios?

16:9 (widescreen) is the modern standard for TVs, monitors, and video. 4:3 was the classic TV and early computer monitor format. 16:9 is wider and better for cinematic content, while 4:3 provides more vertical space, still used in tablets like the iPad.

  • 16:9 decimal = 1.778; 4:3 decimal = 1.333 — 16:9 is 33% wider relative to height
  • 16:9 is standard for YouTube, streaming, HDTV, and most computer monitors
  • 4:3 is used by iPads, many e-readers, and classic 35mm presentations
  • 16:9 at 1080p = 1920×1080 (2.07 MP); 4:3 at similar pixel count = 1600×1200 (1.92 MP)
  • Displaying 4:3 content on 16:9 screens adds black bars (pillarboxing) on the sides
Feature16:94:3
Width vs Height78% wider than tall33% wider than tall
Common Resolution1920×10801024×768
Primary UseVideo, gaming, monitorsTablets, legacy displays
Cinema FeelWidescreen / cinematicClassic / boxy
Q

What are megapixels and how do they relate to aspect ratio?

Megapixels (MP) measure total pixel count: width × height ÷ 1,000,000. A 1920×1080 image is 2.07 MP. Aspect ratio and megapixels are independent — both 3840×2160 (16:9, 8.3 MP) and 2880×2880 (1:1, 8.3 MP) are 8.3 megapixels despite different ratios.

  • 1920×1080 = 2,073,600 pixels = 2.07 MP
  • 3840×2160 = 8,294,400 pixels = 8.29 MP (exactly 4× the pixels of 1080p)
  • Higher MP = more detail for printing and cropping, but larger file sizes
  • A 12 MP phone camera (4000×3000, 4:3) can crop to 16:9 at 4000×2250 = 9 MP
  • Social media compresses photos regardless of MP — 1080px width is usually sufficient

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Last Updated: Jun 11, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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