MP4 compressor
Drop an MP4 and compress it to the size you need — entirely in your browser. It re-encodes to efficient H.264 so the result plays everywhere, and your file is never uploaded.
Drop a video here, or browse
MP4 · MOV · WebM — compressed right here, nothing uploaded
100% on-device · no signup · no watermark
Loading compressor…
Bigger files take longer — your CPU does the work, privately.
A compressor that runs on your device — not a cloud uploader
Most “MP4 compressor” sites upload your file to a server, compress it there, and hand back a download. This one is different: the compression engine runs inside your browser with WebAssembly, so the MP4 never leaves your device. There’s no upload wait, no queue, and no copy kept on someone else’s server.
It reads your MP4, re-encodes the video to H.264 and the audio to AAC at the bitrate needed for your target, and gives you a standard .mp4 back — the most compatible format there is, accepted by Discord, WhatsApp, email, editors and every social platform.
The two settings that decide MP4 size
Bitrate is the big one: it’s the data spent per second, and lowering it is what shrinks the file. Resolution is the other — a 4K MP4 holds four times the pixels of 1080p, so downscaling a clip you’ll watch on a phone saves a lot with no visible loss. The compressor handles both from a single target.
Pick a platform preset or set an exact size, and it works backwards from your clip’s length to the right bitrate. You never touch codecs or command lines — just the size you want.
Frequently asked questions
Is this MP4 compressor free?
Yes — completely free, with no signup, no email and no watermark. Because the work happens in your browser instead of on a server, there’s no cost to gate behind a paid plan.
How much can it compress an MP4?
As much as you ask — you set the target size. A high-bitrate phone or screen recording can often drop to a fraction of its size while staying perfectly watchable; how far you can push depends on the clip’s length and motion.
Does it keep the MP4 format?
Yes. The output is a standard H.264 + AAC MP4, the most widely compatible combination. It also reads MOV and WebM and outputs MP4, so you can convert and compress in one step.
Does my MP4 get uploaded?
No. The MP4 is compressed entirely in your browser and never sent to a server — the engine loads once from a CDN, then it even works offline.