Video Compressor
Upload a video to compress or drag and drop
MP4, MOV, WebM, MKV and more. Everything happens in your browser - nothing is uploaded.
Runs entirely in your browser using ffmpeg compiled to WebAssembly. Your video is never uploaded. Large videos take longer and use more memory, so very large files may be slow on a phone.
Shrink a video so it fits an upload limit, sends faster, or takes less space, without a big drop in quality. Upload an MP4, MOV, WebM, or MKV, pick a quality level and an optional lower resolution, and download a smaller MP4. It re-encodes the video with efficient settings and shows you exactly how much smaller the result is. Everything runs in your browser with ffmpeg compiled to WebAssembly, so the video is never uploaded.
How to use this tool
- 1Upload a video (MP4, MOV, WebM, MKV, and more).
- 2Pick a quality: High, Balanced, or Small file.
- 3Optionally cap the resolution (1080p, 720p, or 480p) for a bigger saving.
- 4Click Compress video and wait - longer clips take longer.
- 5Check the before and after sizes, then download the compressed MP4.
Example
Upload a large MP4, choose Balanced quality and cap the resolution at 720p, and compress. The result is often a fraction of the original size while still looking good on a phone or laptop.
Upload a screen capture, keep the original resolution, and choose Small file. Screen recordings compress well, so you usually get a large size reduction with little visible change.
Common use cases
- Getting a video under an email or upload size limit
- Shrinking a screen recording before sharing it
- Reducing a phone video so it uploads faster on a slow connection
- Saving storage space on a folder full of large clips
- Preparing a smaller video for a website or messaging app
Common mistakes
- Expecting an already-compressed video to shrink a lot - if a file was already optimised, choose a lower quality or resolution to see a real saving.
- Keeping full resolution when you do not need it - dropping to 720p or 480p is the single biggest lever on file size.
- Compressing a very long video on a phone - it uses a lot of memory and time; use a desktop for large files.
- Choosing High quality and expecting a small file - High keeps more detail, so the file stays larger; use Balanced or Small for maximum saving.
Frequently asked questions
Is my video uploaded anywhere?
No. Compression runs entirely in your browser using ffmpeg compiled to WebAssembly. The video never leaves your device, which makes it safe for private or unreleased footage.
How much smaller will my video get?
It depends on the original. Videos straight from a camera or screen recorder often shrink a lot, while already-compressed files shrink less. Lowering the resolution and choosing a smaller-file quality gives the biggest reduction, and the tool shows the exact percentage saved.
Will compressing lose quality?
Some quality is traded for size, but the Balanced setting is tuned to look nearly identical for most footage. If you need to keep more detail, choose High quality; if size matters most, choose Small file.
Which formats can I compress?
Common formats all work as input: MP4, MOV (iPhone and Mac), WebM, and MKV, among others. The output is always an MP4, which plays on virtually any device.
Why is it slow on a big video?
Re-encoding video is heavy work, and it runs on your own device rather than a server. Longer and higher-resolution videos take more time and memory, so large files are best compressed on a desktop rather than a phone.
Does it keep the audio?
Yes. The audio track is kept and re-encoded to a compact AAC stream, so the compressed MP4 still has sound. Only the file size changes, not the presence of audio.
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