Compress Video in Your Browser
Make big videos smaller without uploading them anywhere. The compression runs on your own device using a WebAssembly build of FFmpeg, so your footage stays private — with no watermark and no size paywall.
Drop in a video, pick a quality level and optional resolution, and the tool re-encodes it to a smaller H.264 MP4 entirely in your browser using FFmpeg compiled to WebAssembly. Nothing is uploaded — only the FFmpeg engine downloads once. Larger videos take longer because all the work happens on your device.
Drop a video to compress
Outputs a smaller H.264 MP4 — nothing is uploaded
Zero Server Uploads
Files process in local RAM
Instant WASM Speed
No waiting queues or lags
Unlimited Batching
Convert files without limits
Suggest a Feature or Improvement for Video Compressor
Need custom options, higher limits, or extra format support? Let our engineering team know!
How to use Video Compressor
- 1Drop in a video file (MP4, MOV, WebM, MKV, AVI).
- 2Choose a quality level — smaller file, balanced, or high quality — and optionally lower the resolution.
- 3Click Compress; FFmpeg re-encodes the video on your device with a progress bar.
- 4Compare the before/after size and download the smaller video.
How in-browser compression works
This tool runs FFmpeg — the same engine behind most video software — compiled to WebAssembly so it executes inside your browser tab. Your video is read into memory, re-encoded to efficient H.264, and handed back as a download. It is never uploaded to a server.
The FFmpeg engine (about 30 MB) downloads the first time you use the tool and is then cached. After that, only your own video is processed, entirely on your device.
Choosing a quality level
Compression trades some visual quality for a much smaller file. 'Smaller file' pushes size down hardest, 'Balanced' is a sensible default, and 'High quality' keeps the video closest to the original while still saving space. Lowering the resolution (for example 1080p → 720p) shrinks the file further and is often invisible on phones.
Because the work runs on your device, speed depends on your computer and the video's length and resolution — a long 4K clip can take several minutes. There's a live progress bar so you always know where it's up to.
Why compress in your browser
Most online video compressors upload your footage to their servers, add a watermark, or cap the file size until you pay. That's a real privacy problem for personal videos, and a hassle for large files. Here the video never leaves your device, there's no watermark, and the only practical size limit is your device's memory.
It's ideal for emailing a clip, fitting a video under an upload limit, saving phone storage, or sharing footage you'd rather not hand to a third-party server.
Frequently Asked Questions
Is my video uploaded to a server?
No. Compression runs entirely in your browser via a WebAssembly build of FFmpeg, so the video is processed on your device and never uploaded. Only the FFmpeg engine itself is downloaded once, then cached.
Is there a watermark or file-size limit?
No watermark, ever, and no artificial size cap — the practical limit is your device's available memory. Very large or long videos simply take longer to process.
Why is it slower than other online compressors?
Because the work happens on your own device instead of a powerful server. That's the trade for privacy: nothing is uploaded. A fast preset keeps it as quick as possible, and there's a progress bar.
What formats can I compress?
MP4, MOV, WebM, MKV, AVI and M4V go in; the tool outputs a compressed H.264 MP4, which plays on virtually every device and platform.
Is it free, and are there limits?
It's completely free with no account required. Because processing happens on your device, there's no per-file upload limit — the practical ceiling is your device's available memory. You can batch many files and download them as a single ZIP.