Aspect Ratio Calculator for Images & Video
Calculate missing dimensions, simplify width and height into a ratio, and scale image or video sizes for common formats like 16:9, 4:3, 1:1, and 9:16.
An aspect ratio calculator keeps image or video dimensions proportional when one side changes.
For 16:9, 1920px wide becomes 1080px high; for 9:16, 1080px wide becomes 1920px high.
Use the final platform ratio
Choose 16:9 for widescreen, 1:1 for square thumbnails, 4:5 for portrait cards, and 9:16 for vertical stories.
Round carefully
Pixel dimensions may need rounding, so check platform minimum sizes before exporting images or videos.
16:9 is common for widescreen video and thumbnails. 1:1 is common for square posts. 9:16 is common for vertical video. 3:2 and 4:3 are common in photography and presentations.
The calculator focuses on dimensions and ratios only; it does not resize or upload image files.
Example
A 16:9 image at 1280px wide should be 720px high because 1280 x 9 / 16 = 720.
Assumption
The calculation preserves geometric proportions. It does not inspect image content or decide crop positioning.
Limitation
Rounded pixel dimensions can create a tiny ratio difference. Platform-safe areas and compression rules are not included.
Image resize planning
Calculate missing width or height before resizing a JPG, PNG, or WEBP image.
Video thumbnails
Plan 16:9, 9:16, or 1:1 dimensions for video covers and social previews.
Design handoff specs
Translate aspect ratios into exact pixel dimensions for product cards and content slots.
Crop preparation
Pick target dimensions before using the image cropper for square, portrait, or widescreen crops.
What size is 16:9 at 1920px wide?
At 1920px wide, a 16:9 image or video is 1080px high because 1920 × 9 ÷ 16 = 1080.
What aspect ratio is 1080 by 1920?
1080 by 1920 simplifies to 9:16, which is a common vertical video format.
Can I use this before cropping an image?
Yes. Use the calculator to decide the target dimensions, then crop the file with the Image Crop Tool.
Does this tool upload my image?
No. This page only calculates dimensions and ratios in the browser. It does not upload files or call an external API.
Suggested workflow
Image sizing path
Move from ratio math to crop and final export prep when a visual asset needs exact dimensions.