ALTools
Compress Video
Reduce video file size with adjustable quality presets. Ideal for sharing and uploads.
How to use this tool — step-by-step guideHow Video Compression Works
Upload a video file—MP4, MOV, WebM, and other common formats are supported. ALTools processes it on your device; files are never sent to a server and no account is required.
Pick a quality preset from Very low through Very high, or choose Original to keep resolution while re-encoding. Processing runs entirely in your browser with live progress. Turn on optional H.265 when supported for smaller MP4s at similar visual quality.
Compression helps when uploads hit size limits on email, chat apps, or social platforms, when you need faster publishing, or when you want to free storage on a phone or laptop without deleting projects.
Lower presets shrink files more aggressively and trade away detail; higher presets stay closer to the source. Longer or higher-resolution videos take more time, but your media never leaves your machine.
The result is a compressed MP4 ready to share or upload. H.265 outputs are smaller when your browser supports them; stick to the default encoder if you need maximum playback compatibility.
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Frequently Asked Questions
Will compression reduce quality?
Yes. Lower presets shrink file size more but use stronger compression. Pick a preset that fits your upload limit and how picky you are about detail.
What quality presets are available?
Choose from Very low through Very high, or Original to keep resolution while re-encoding. Enable optional H.265 when your browser supports it for smaller MP4s — some older devices may not play HEVC.
Are files uploaded?
No — compression runs entirely in your browser.