Aspect Ratio Calculator
Find the ratio of any image and resize it while keeping perfect proportions.
Working with image sizes? Resize a photo online with resize-photo.com
What is aspect ratio?
Aspect ratio is the relationship between an image's width and its height, written as two numbers like 3:2 or 16:9. It describes the shape of the frame, independent of how many pixels it contains. Getting it right keeps photos from being stretched or unexpectedly cropped.
Common photo and video ratios
Most interchangeable-lens cameras shoot 3:2, the shape inherited from 35 mm film. Micro 4/3 and many compacts use 4:3. Video and most screens are 16:9, while social platforms favour 1:1 and 4:5. Knowing your target ratio before you crop saves re-editing later.
Resizing and cropping without distortion
To resize cleanly, keep the same ratio: enter the original width and height, then a new width, and use the matching height this tool returns. If you need a different ratio, crop rather than stretch, so the image keeps its natural proportions instead of looking squashed.
How this calculation works
Formula: ratio = W : H (divided by GCD)
where:
W= widthH= height
Sources:
FAQ
What aspect ratio do most cameras use?
Most interchangeable-lens cameras shoot 3:2, Micro 4/3 shoots 4:3, and many phones default to 4:3 or 16:9.
How do I resize without distortion?
Keep the same ratio: enter your target width and use the new height this tool gives you rather than typing an arbitrary value.
What is the difference between 3:2 and 16:9?
3:2 is the classic still-photo shape from 35 mm film; 16:9 is wider and matches most screens and video, so it crops the top and bottom off a 3:2 frame.
Which aspect ratio is best for Instagram?
Instagram supports 1:1 (square), 4:5 (portrait) and 1.91:1 (landscape); 4:5 uses the most screen space in the feed.