Aspect Ratio Calculator
Enter the width and height in pixels to see the simplified aspect ratio, decimal ratio, and total megapixels.
Aspect Ratio: 16:9
Decimal Ratio:
Megapixels:
Total Pixels:
Aspect Ratio Calculator — Find the Ratio of Any Resolution
An aspect ratio describes the proportional relationship between the width and height of an image, video, or screen. It is written as width:height — for example, 16:9 means for every 16 units of width, there are 9 units of height. Understanding aspect ratios is essential for video editing, photography, web design, and display selection.
How to Calculate Aspect Ratio
The aspect ratio is found by dividing both the width and height by their greatest common divisor (GCD):
Aspect Ratio = Width ÷ GCD : Height ÷ GCD
Example: A 1920×1080 display:
- GCD of 1920 and 1080 = 120
- 1920 ÷ 120 = 16, 1080 ÷ 120 = 9
- Aspect Ratio = 16:9
Common Aspect Ratios and Their Uses
| Ratio | Decimal | Common Resolutions | Usage |
|---|---|---|---|
| 16:9 | 1.778 | 1920×1080, 2560×1440, 3840×2160 | HDTV, YouTube, monitors |
| 16:10 | 1.600 | 1920×1200, 2560×1600 | Laptops, productivity monitors |
| 4:3 | 1.333 | 1024×768, 1600×1200 | Classic TV, iPad, presentations |
| 21:9 | 2.333 | 2560×1080, 3440×1440 | Ultrawide monitors, cinema |
| 1:1 | 1.000 | 1080×1080 | Instagram posts, profile pictures |
| 9:16 | 0.563 | 1080×1920 | TikTok, Instagram Stories, Reels |
| 3:2 | 1.500 | 2160×1440, 6000×4000 | DSLR photos, Surface devices |
| 2.39:1 | 2.390 | varies | Anamorphic cinema (widescreen films) |
Social Media Image Sizes
| Platform | Content Type | Recommended Size | Aspect Ratio |
|---|---|---|---|
| YouTube | Thumbnail | 1280×720 | 16:9 |
| Post | 1080×1080 | 1:1 | |
| Story/Reel | 1080×1920 | 9:16 | |
| Cover photo | 820×312 | ~2.63:1 | |
| Twitter/X | Post image | 1200×675 | 16:9 |
| Banner | 1584×396 | 4:1 | |
| TikTok | Video | 1080×1920 | 9:16 |
Why Aspect Ratio Matters
- Cropping and distortion: Using the wrong ratio stretches or squashes images. A 4:3 photo forced into a 16:9 frame will either crop important content or add black bars.
- Responsive design: Web developers need to maintain ratios across screen sizes. CSS
aspect-ratioproperty makes this easier. - Video production: Shooting in the wrong ratio means post-production headaches. Most modern content targets 16:9 or 9:16.
- Print and photography: DSLR sensors typically shoot at 3:2 while smartphone cameras often use 4:3 or 16:9.
Frequently Asked Questions
What is the most common aspect ratio?
16:9 is the most common aspect ratio for screens and video content. It's used by virtually all modern TVs, monitors, YouTube, and streaming services.
What aspect ratio is 1920x1080?
1920×1080 (Full HD or 1080p) has an aspect ratio of 16:9. This is the standard for high-definition video and the most common monitor resolution.
What aspect ratio should I use for Instagram?
Instagram supports 1:1 (square posts), 4:5 (portrait posts — recommended for feed), and 9:16 (Stories and Reels). For maximum visibility in the feed, use 1080×1350 (4:5).
How do I maintain aspect ratio when resizing?
To maintain the aspect ratio when resizing, change only the width or height and calculate the other dimension proportionally. If the original is 1920×1080 (16:9) and you set width to 1280, the height should be 1280 ÷ (16÷9) = 720.
What is the difference between 16:9 and 16:10?
16:10 is slightly taller than 16:9, giving about 11% more vertical space. 16:10 is common on laptops and productivity monitors, while 16:9 dominates TVs and gaming monitors.
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