Compress Video in Your Browser
Reduce video file size locally in your browser with Fast 720p, Balanced and Smallest presets - your file never leaves your device.
Compress a video right in your browser: the file is re-encoded to H.264 (720p Fast preset by default) so it gets dramatically smaller, and nothing is ever uploaded - processing is local, private and free. Hardware-accelerated when your browser supports it.
Choose a file or drop it here
🔒 Processed locally — never uploaded.
Large video files are awkward to share - email bounces them, chat apps refuse them, and uploads crawl. This tool re-encodes your video with the same battle-tested engine professionals use (FFmpeg), tuned to cut file size dramatically while keeping quality you would be happy to share. Unlike most online compressors, it does the work on your device: nothing is uploaded, so it is private by design and there is no queue.
How it works
- Pick a video from your device or drop it into the box above. The file opens directly in your browser's memory - it is never uploaded anywhere.
- On first use the compression engine (FFmpeg built as WebAssembly, about 31 MB) is downloaded once and cached. You will see its progress before compression starts.
- The video is re-encoded to H.264 at CRF 28 - a quality-size sweet spot - and the audio is converted to AAC. When it finishes, a download button appears with the new file size.
Common uses
- Fit a clip under a messaging or email attachment limit (many platforms cap uploads around 10-25 MB).
- Shrink screen recordings before sharing them in a bug report or support ticket.
- Reduce phone videos before backing them up or to free up storage.
- Prepare lecture or meeting recordings for platforms with strict upload limits.
Supported formats and limits
| Input containers | MP4, MOV, WebM, MKV, AVI |
|---|---|
| Input video codecs | H.264/AVC, H.265/HEVC, VP8, VP9, MPEG-4 |
| Output | MP4 - H.264 video (CRF 28) with AAC audio |
| Maximum file size | 500 MB (in-browser memory limit; a caution shows above ~300 MB on mobile) |
| Where it runs | Entirely in your browser (WebAssembly) - keeps working offline once loaded |
Frequently asked questions
Is my video uploaded to a server?
No. The entire compression runs inside your browser using FFmpeg compiled to WebAssembly. Your file never leaves your device - you can even switch off your connection once the page has loaded and it will still work.
How much smaller will my video get?
It depends on the source. Phone recordings and screen captures often shrink by 40-80% because they were encoded quickly at high bitrates. Videos that were already carefully compressed will shrink less.
Why do long videos take a while?
On most modern browsers with MP4 input, compression runs on your device's hardware encoder and finishes many times faster. When hardware acceleration is not available (other formats or older browsers), processing falls back to a single-core WebAssembly engine, which is slower - the Fast 720p preset is the quickest option there. Either way the progress bar shows real progress.
Does compressing reduce quality?
Slightly, by design. We re-encode with H.264 at CRF 28, a setting chosen to keep videos looking close to the original at a much smaller size. Fine textures or fast motion may look a bit softer.
Which input formats are supported?
Most common formats: MP4, MOV, WebM, MKV and AVI containers with H.264, H.265/HEVC, VP8, VP9 or MPEG-4 video. The output is always an MP4 (H.264 video, AAC audio) that plays everywhere.
Is there a size limit?
Files up to 500 MB are supported. The engine keeps the whole file in browser memory while processing, so very large files can exhaust it - that is why the limit is honest rather than optimistic. On mobile devices we show a caution above roughly 300 MB. Support for larger files via chunked processing is on our roadmap.
Is this really free?
Yes - free, with no signup, no watermark and no queue. Because the work happens on your device, there are no per-file server costs to pass on to you.