About this video compressor & trimmer
This compressor runs ffmpeg, the same engine used by professional video software, compiled to WebAssembly. Your video stays on your device while it is re-encoded with the H.264 codec into an MP4 that plays everywhere, from WhatsApp to Instagram to email.
How to use the Video Compressor & Trimmer
- Drop the video you want to shrink. You will see its size, length and resolution.
- Choose a quality level and resolution. Balanced + 720p usually cuts size by 60–90%.
- Optionally set a trim start and end: play to a moment and press Use current.
- Press Compress video, compare sizes before and after, preview, and download the MP4.
Features
- Real H.264 (x264) encoding with CRF quality control and AAC audio.
- Resolution downscaling that works for both landscape and vertical Reels/Shorts.
- Trim to a start and end time in the same pass.
- Before/after size comparison and an instant preview of the result.
Frequently asked questions
How do I compress a video for WhatsApp or email?
Choose Balanced or Small quality and 720p or 480p. Phone clips usually shrink to a fraction of their size, so they send faster and fit email attachment limits (often 20–25 MB). For very long videos, trim them or choose 360p.
Why does compression take a while?
Encoding is done by your own device’s processor in a single thread, so it is slower than a desktop app. Shorter clips, lower resolution and the Fastest speed setting help most.
Is there a file size limit?
There is no upload limit because nothing is uploaded, but browsers cap memory at roughly 2 GB, so files above ~400 MB may fail. Trim long recordings first.
Will the quality drop?
Some detail is always lost when compressing. High keeps it close to the original; Small and Smallest are best for messaging where file size matters most.
Which formats can I compress?
MP4, MOV (iPhone), WebM, MKV, AVI and most common formats. The output is always MP4 (H.264 + AAC) for maximum compatibility.