Compress Video Online

Shrink a video to a fraction of its size, in your browser, with hardware-accelerated encoding where your browser offers it. Pick a resolution and quality; get an MP4 that plays everywhere.

The converter is ffmpeg compiled to WebAssembly. It downloads once (30 MB) when you pick your first file, then stays in your browser cache.

Medium is the sensible default: clearly smaller, hard to tell apart in motion. The output is an MP4 (H.264 video, AAC audio), which plays everywhere.

Your file is processed by your own browser and never uploaded. The engine itself is a one-time 30 MB download the first time you use it, and after that it comes out of your browser cache.

How to use Video Compressor

  1. 1Drop one or more videos onto the box above, or click to pick them.
  2. 2Choose a resolution cap and quality below if the defaults are not right. Medium at 720p is a good starting point for sharing.
  3. 3Download each compressed MP4. The row shows the before and after sizes, so you know what you traded.

Where the size actually goes

Video size is bitrate times duration, nothing more. Cameras and screen recorders choose bitrates generously because storage on the device is cheap and quality is their headline, so a five-minute phone clip can be a gigabyte. Almost all of it is headroom you cannot see. This tool re-encodes the video at a bitrate matched to its resolution, frame rate and your chosen quality level, which is where the 60 to 90 percent reductions come from.

Two controls decide the outcome. Resolution is the blunt, powerful one: halving the frame's dimensions quarters the pixels. Quality is the fine one: it sets how many bits each pixel gets. The defaults, medium quality with a 720p cap, are chosen for the commonest job, which is making a file small enough to send without making it embarrassing to watch.

Fast path, slow path

Browsers have started exposing the same hardware video encoders that phones use for recording. Where yours does, this tool encodes on that hardware, and a minute of 1080p goes by in seconds. Where it does not, a software encoder compiled to WebAssembly does the identical job, universally but slower than real time. The result is the same MP4 either way; only the wait differs. Every step of both paths runs on your machine, and the footage never leaves it.

What to expect, honestly

Compression is lossy and one-way. Re-compressing an already-small file buys little and costs quality, and a video compressor worth trusting reports when a result did not shrink rather than handing it over silently, which this one does. Files up to 500 MB are accepted. For a feature-length archive job, desktop software with hours to spend is still the better instrument; for everything up to that, this page does the work where the file already is.

Frequently asked questions

How much smaller will my video get?
It depends entirely on how generous the source's bitrate was, which is why the row reports real numbers instead of this page promising one. Phone recordings and screen captures are typically encoded far above what their content needs, and shrinking them 60 to 90 percent at the medium setting is normal. A video that was already compressed aggressively has little left to give, and the tool will tell you when the result is not smaller.
Does compressing reduce quality?
Yes, by definition; compression is a trade of quality for size, and anyone who says otherwise is selling something. What this tool does is make the trade visible and adjustable. High keeps the loss hard to notice, medium is hard to tell apart in motion on a phone screen, and low visibly compresses but stays watchable. Compression also cannot be undone, so keep the original if it matters.
Why is it fast on my laptop but slow on another machine?
When the browser exposes hardware video encoding, this tool uses it, and the run finishes in a fraction of the clip's length. Where that is unavailable, it falls back to a software encoder compiled to WebAssembly, which is universal but slower than real time. Chrome and Edge on ordinary hardware take the fast path for MP4 and MOV files; other combinations may take the slow one.
What does the resolution setting do?
It caps the shorter side of the frame, so 720p means the same thing for portrait and landscape footage. Resolution is the strongest lever on file size, because bytes scale with pixel count. A video watched on a phone gains nothing from staying 4K; capping it at 1080p or 720p saves more than any quality slider will.
What formats can I feed it, and what comes out?
MP4, MOV, MKV, WebM, AVI and most other common containers go in. What comes out is always MP4 with H.264 video and AAC audio, because a compressed file exists to be shared, and that pairing is what every phone, chat app and browser accepts.

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