Aspect Ratio Calculator
Calculate aspect ratios from dimensions or find missing dimensions from a known ratio. Perfect for responsive design, video, and images.
Calculate Ratio from Dimensions
Calculate Missing Dimension
Common Presets
Common Screen Resolutions
| Name | Resolution | Ratio |
|---|---|---|
| HD (720p) | 1280 x 720 | 16:9 |
| Full HD (1080p) | 1920 x 1080 | 16:9 |
| 2K (QHD) | 2560 x 1440 | 16:9 |
| 4K (UHD) | 3840 x 2160 | 16:9 |
| iPad | 2048 x 1536 | 4:3 |
| iPhone 15 Pro | 1179 x 2556 | ~9:19.5 |
| Ultrawide | 3440 x 1440 | 21:9 |
How to Use the Aspect Ratio Calculator
- 1.To find a ratio: enter Width and Height in the left panel. The simplified ratio appears instantly.
- 2.To find a missing dimension: set the desired ratio (e.g., 16:9) in the right panel.
- 3.Choose whether you know the Width or Height and enter the known value.
- 4.Use the Common Presets buttons to quickly load popular aspect ratios.
Frequently Asked Questions
What is an aspect ratio?
An aspect ratio is the proportional relationship between the width and height of an image, screen, or video. It is expressed as two numbers separated by a colon, e.g., 16:9. It describes the shape rather than the actual size.
What is the most common aspect ratio?
16:9 is the most common aspect ratio for monitors, TVs, and video content (HD, Full HD, 4K). Other popular ratios include 4:3 (classic TV/iPad), 1:1 (Instagram square), and 9:16 (vertical mobile video).
How do I maintain aspect ratio when resizing?
To maintain the aspect ratio when resizing, change only one dimension (width or height) and calculate the other using this tool. The formula is: new_height = new_width * (original_height / original_width).
What aspect ratio is best for social media?
It depends on the platform: Instagram feed posts use 1:1 or 4:5, Stories/Reels use 9:16, YouTube thumbnails use 16:9, Twitter images work best at 16:9 or 2:1, and Facebook posts use 1.91:1 for link previews.