Calculate aspect ratios from dimensions, resize images while maintaining proportions, and find the perfect resolution for any project. Essential tool for content creators, gamers, and designers.
Enter your image or screen dimensions to calculate the aspect ratio. The calculator will simplify to the smallest whole number ratio.
Find the perfect aspect ratio for your specific use case
Popular screen and content resolutions with their aspect ratios
| Name | Resolution | Aspect Ratio | Megapixels |
|---|---|---|---|
| 8K UHD | 7680 × 4320 | 16:9 | 33.18 MP |
| 4K UHD | 3840 × 2160 | 16:9 | 8.29 MP |
| 1440p QHD | 2560 × 1440 | 16:9 | 3.69 MP |
| 1080p Full HD | 1920 × 1080 | 16:9 | 2.07 MP |
| 720p HD | 1280 × 720 | 16:9 | 0.92 MP |
| 4K DCI | 4096 × 2160 | 1.89:1 | 8.85 MP |
| Instagram Square | 1080 × 1080 | 1:1 | 1.17 MP |
| Instagram Portrait | 1080 × 1350 | 4:5 | 1.46 MP |
| TikTok/Reels | 1080 × 1920 | 9:16 | 2.07 MP |
| YouTube Thumbnail | 1280 × 720 | 16:9 | 0.92 MP |
| iPhone 15 Pro | 2796 × 1290 | 19.5:9 | 3.61 MP |
| iPad Pro 12.9" | 2732 × 2048 | 4:3 | 5.60 MP |
Aspect ratio describes the proportional relationship between width and height of an image, screen, or video. It is expressed as two numbers separated by a colon, like 16:9 or 4:3. These numbers represent the ratio of width to height in their simplest form. For example, a 16:9 aspect ratio means that for every 16 units of width, there are 9 units of height.
Understanding aspect ratios is crucial for content creators because using incorrect ratios can result in cropped, stretched, or letterboxed content across different platforms and devices. Each platform and use case has optimal aspect ratios that ensure your content displays correctly and looks professional.
Aspect ratios determine how content appears across different screens and platforms. Using the wrong aspect ratio can lead to several issues: images may be cropped, cutting off important content; videos may display with black bars (letterboxing or pillarboxing); or content may appear stretched and distorted.
Modern displays predominantly use 16:9 (widescreen) aspect ratio, which has become the standard for TVs, computer monitors, and most video content. However, social media platforms often require different ratios: Instagram favors 1:1 (square) and 4:5 (portrait) for feed posts, while TikTok and Instagram Stories use 9:16 (vertical). Professional photographers often work with 3:2 (matching 35mm film) or 4:3 ratios depending on their camera sensor.
To calculate aspect ratio from dimensions, you need to find the greatest common divisor (GCD) of the width and height, then divide both dimensions by this number. For example, with a 1920×1080 resolution, the GCD is 120. Dividing both by 120 gives us 16:9. You can also express aspect ratio as a decimal by dividing width by height: 1920÷1080 = 1.778, which is the decimal form of 16:9.
When resizing images or videos, maintaining the original aspect ratio prevents distortion. To resize proportionally, calculate the aspect ratio as a decimal (width ÷ height), then use these formulas when changing dimensions: If changing width, new height equals new width divided by aspect ratio. If changing height, new width equals new height multiplied by aspect ratio.
For example, if you have a 1920×1080 image (aspect ratio 1.778) and want to resize to 1280 pixels wide: new height = 1280 ÷ 1.778 = 720 pixels. The result is 1280×720, which maintains the 16:9 aspect ratio. Most image editing software includes a constraint proportions or lock aspect ratio option that automatically does these calculations when you resize.