About the free video compressor
Compressing video normally means either installing desktop software or uploading gigabytes to a website and waiting for a server to send them back. This tool takes a third path: it uses WebCodecs, the hardware-accelerated video engine built into modern browsers, to re-encode the video directly on your device. A phone clip compresses in seconds, a long recording never spends a minute uploading, and no copy of your footage ever exists anywhere but your own machine. Because we pay for no servers or bandwidth, the tool has no file size caps, no queue, and no daily limits.
You choose either a percentage of the original size or an exact target size, and the tool works backwards from that byte budget. It reads the video's duration and audio bitrate, calculates the video bitrate that lands under your target, and re-encodes at exactly that rate. This is the same math you would do by hand in a desktop encoder, automated. The size presets cover the limits people actually hit: 10 MB for email attachments and chat apps, 25 MB for messaging platforms, 50 and 100 MB for forums and learning platforms.
Getting good quality at small sizes
Bitrate is quality spread over time: the same 10 MB looks great on a 20 second clip and terrible on a 5 minute one. If your result looks blocky, the honest fixes are a bigger target, a shorter video, or fewer pixels. Lowering the resolution helps more than people expect, because a 720p video needs roughly half the bitrate of 1080p to look clean, so at aggressive targets the 720p cap usually looks better than full resolution. If you only need part of the video, cut it first with the free video trimmer so the bitrate budget is spent only on the seconds you keep.
What people use it for
The most common jobs are fitting clips under messaging and email limits, shrinking screen recordings before sharing them in tickets or pull requests, compressing phone footage to free up storage, and preparing previews of large project files for clients. Creators compress gameplay and OBS recordings before uploading to platforms that will re-encode the video anyway, and AI video makers shrink generated clips from tools like Sora, Veo, and Kling for quick sharing. If a clip matters enough to keep at full quality, compress a copy, not the original.
Formats, browsers, and limits
The tool accepts MP4, MOV, WebM, and MKV files. MP4 and MOV come back as MP4, WebM and MKV come back as WebM. It runs in current versions of Chrome, Edge, Safari, and Firefox; browsers without WebCodecs cannot process video locally and will say so instead of failing silently. Very long videos are limited only by your device's memory, and a good rule of thumb is to stay under about 2 GB per file. Compression permanently discards detail, and if you later need a compressed clip to look sharp again, Upsampler's premium AI Video Upscaler restores resolution and detail up to 4K. You can preview the effect with the free AI video upscaler.