Free tool
Free video resizer and aspect ratio converter
Resize a video or change its aspect ratio in your browser.
Your video
Drag a file here, paste it, or choose one.
.mp4, .mov, .webm, .mkv. Up to 500 MB.
Up to 10 minutes long.
Your video never leaves your browser. The resize runs on this machine.
Output: 1080 by 1920.
Result
Worked example
Measured on our own 27 second launch film at 1920 by 1080, the 9:16 preset with crop to fill.
Before
7.6 MB
After, 1080 by 1920
3.1 MB
A 16:9 frame cropped to 9:16 throws away most of the width, so anything you care about has to be near the middle. Pad with a colour instead when there is text close to the edges.
1. Drop in a video. 2. Pick an aspect ratio. 3. Choose crop, pad or stretch. 4. Download the result.
What Interlace does
Made for vertical, not cropped to vertical.
- Pick 9:16, 16:9 or 1:1 before the video is made
- Scenes are composed for that frame, so nothing important falls off the edge
- Same script, in each format you need
Real Interlace output, unedited. Shown silent and sped up.
Cropped from 16:9
Cropping 16:9 to 9:16 cuts away two thirds of the picture.
Questions
Asked and answered
No. The file is read by the page, handed to ffmpeg compiled to WebAssembly, and written back out, all on your own machine. There is no upload step, and closing the tab discards everything.
Crop to fill scales the video up until it covers the new frame and cuts off whatever hangs over the edge, which is what you want for a 16:9 clip going to Reels. Pad keeps the whole frame and fills the gap with a colour, which is safer when there is text near the edges. Stretch keeps the whole frame with no bars by pulling the picture to the new shape, so people and text look wider or narrower.
Yes. Pick Stretch, then a preset or a custom width and height. Each side is scaled on its own, so a 4:3 clip stretched to 1920 by 1080 fills the whole 16:9 frame and comes out wider. The pixel aspect ratio is reset to square, so players show the stretched shape instead of quietly undoing it.
16:9 is 1920 by 1080, 9:16 is 1080 by 1920, 1:1 is 1080 by 1080, 4:5 is 1080 by 1350, and 4:3 is 1440 by 1080. Custom takes any even width and height you type.
500 MB and 10 minutes. Everything runs inside one browser tab, and a tab has a fixed memory budget. Past those limits the run gets slow or fails outright, so a desktop encoder is the better tool.
The WebAssembly build here is single threaded, on purpose. The multi threaded build needs cross-origin isolation headers that would break embedded video elsewhere on this site. Expect roughly real time on a modern laptop, so a two minute clip takes about two minutes.
Turn this into a video
Create an account and start from a document, script, or prompt.