Aspect Ratio Calculator
Resize an image or video while keeping the same proportions. Enter the original dimensions, choose a new width or height, and get the matching dimension instantly.
1280 × 720
Nearest whole-pixel dimensions at the same aspect ratio.
The calculator preserves proportions. It does not crop, stretch, or add padding to the image or video.
Common aspect ratios and sizes
These are familiar examples, not limits. Any dimensions with the same ratio keep the same shape.
| Aspect ratio | Common example | Typical use |
|---|---|---|
| 16:9 | 1920 × 1080 | Widescreen video and displays |
| 9:16 | 1080 × 1920 | Vertical video and stories |
| 1:1 | 1080 × 1080 | Square images and posts |
| 4:3 | 1600 × 1200 | Classic displays and photography |
| 3:2 | 1500 × 1000 | Photography |
| 5:4 | 1280 × 1024 | Legacy displays and graphics |
Keep the same proportions while resizing
Aspect ratio describes the proportional relationship between width and height. A 1920 × 1080 image simplifies to 16:9. A 1280 × 720 image is also 16:9, so both have the same shape even though their resolutions are different.
Changing only one dimension without adjusting the other can stretch or squash the image. This calculator changes the matching dimension for you so the original proportions stay intact.
Aspect ratio FAQ
How do I calculate aspect ratio?
Divide both dimensions by their greatest common divisor when the dimensions are whole numbers. For example, 1920 and 1080 divide down to 16 and 9, giving a 16:9 aspect ratio.
What aspect ratio is 1920 × 1080?
1920 × 1080 is 16:9, with a decimal width-to-height ratio of about 1.778:1.
What aspect ratio is 1080 × 1920?
1080 × 1920 is 9:16. It is the vertical version of 16:9 and is common for portrait video.
What is the difference between aspect ratio and resolution?
Resolution is the actual number of pixels, such as 1920 × 1080. Aspect ratio describes the shape of those dimensions, such as 16:9. Many different resolutions can share the same aspect ratio.
Does resizing with the same aspect ratio crop the image?
No. Proportional resizing changes width and height together. Cropping removes part of the image, which is a different operation.
Can I use this for video and images?
Yes. The proportion calculation is the same for video frames, photos, thumbnails, graphics and display resolutions.