Media Doctor · Free tool
Turning a widescreen video into a vertical or square one? Enter its size to get the ratio, a resized size that keeps it, and the exact crop or padding for 9:16, 1:1, 4:5 and more.
Runs in your browser. It only does arithmetic; no file is read or uploaded.
Windows apps from SteveShines
Resize for vertical or square and cut the video, without uploading it.
Cut video, remove silence and add captions.
Compress, convert to MP4 and fix playback errors.
Video downloader and local media toolkit.
Divide the width and the height by their greatest common divisor. 1920 and 1080 share 120, so 1920×1080 is 16:9. To resize, multiply the new width by height ÷ width: 1280 × 1080 ÷ 1920 = 720.
Need to know how big the result will be? Use the Video Size Calculator.
16:9. Divide both sides by their greatest common divisor (120) to get 16 and 9. 1280×720, 2560×1440 and 3840×2160 are 16:9 as well.
1080×1920 is the most common size for vertical short video. 720×1280 is the same ratio at a smaller size. Enter your source size and 9:16 above to see how much a crop keeps.
Crop it. A centered 9:16 crop of 1920×1080 is 608×1080, which keeps about a third of the picture, so choose which part to keep or follow the subject. To keep the whole picture instead, pad it onto a 1080×1920 canvas with bars above and below.
Most video uses 4:2:0 chroma subsampling, so H.264 and HEVC encoders need widths and heights divisible by 2. The calculator rounds every result to an even number.
Crop fills the new frame and cuts off the edges that do not fit. Pad keeps the whole picture and fills the empty space with bars (letterboxing or pillarboxing).
No. The calculator only does arithmetic in your browser and never reads a file.