How to compress a video
Three things decide how big a video file is. Change any of them and the file shrinks.
- Resolution. How many pixels per frame. Going from 1080p to 720p roughly halves the file.
- Length. Cutting the dead air off the front and back is the fastest win, and it costs nothing in quality.
- Bitrate. How much data per second the encoder is allowed to spend. This is the dial that trades file size against how clean the picture looks.
Most people reach for bitrate first. Try length and resolution first, because neither one makes the picture look worse at normal viewing size.
Make a video smaller in your browser
Our editor does all three, in your browser, with no upload:
- Drop the video in.
- Trim off anything you do not need. Drag the in and out handles, or press I and O.
- Under Output, set Size to 1080, 720 or 480. That is the short side of the frame.
- Press Export.
A two minute 4K clip cut to forty seconds at 720p will typically come out ten to twenty times smaller than the original.
How small does it need to be?
- Email attachments usually cap at 20 to 25 MB.
- WhatsApp caps at 64 MB and compresses hard on its own anyway.
- Instagram and TikTok re-encode whatever you give them. Uploading a huge file does not help, and a 1080p export is plenty.
That last point is worth repeating. Every social platform re-encodes your upload. Exporting at 4K to preserve quality does nothing except cost you upload time.
Questions
Does compressing a video lose quality?
Lowering the resolution or the bitrate does, by definition. Trimming length does not. Changing container from MOV to MP4 does not.
What is the best format for a small file?
MP4 with H.264 video. It is the most widely supported combination, and it is what our editor exports.
Why is my iPhone video so large?
iPhones record at high bitrates, and 4K at 60 frames per second is roughly 400 MB per minute. Dropping to 1080p is usually all you need.