Video Compressor
Shrink video file sizes while keeping them looking good. Three compression levels to choose from.
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How to compress videos in your browser
This free Video Compressor reduces the file size of MP4, WebM, MOV, and AVI videos entirely in your browser. No upload, no watermark, no signup — your files never leave your device. Powered by ffmpeg compiled to WebAssembly, it re-encodes video locally with H.264 for maximum compatibility and compression.
Features
- Compress MP4, WebM, MOV, and AVI videos — no upload required
- Three compression levels: Light (~20-30% smaller), Medium (~40-60%), Heavy (~60-80%)
- Optional resolution scaling: Original, 1080p, 720p, 480p
- Audio control: keep or remove audio track for additional size savings
- Output as MP4 (H.264 + AAC) with faststart for instant playback
- File size comparison shows original vs compressed size with percentage saved
- No watermark, no signup, no usage limits
- 100% client-side — private and free forever
How video compression works
The compressor uses H.264 encoding with CRF (Constant Rate Factor) to control quality. CRF works by allocating more bits to complex scenes and fewer bits to simple scenes, producing consistent visual quality at the smallest possible file size. Lower CRF values mean better quality but larger files. The Light preset (CRF 23) preserves near-original quality. Medium (CRF 28) offers a good balance. Heavy (CRF 33) prioritizes file size reduction.
Why use a no-upload video compressor?
Most online video compressors upload your files to a server for processing. This tool is different — everything runs in your browser using WebAssembly. That means faster processing with no queue, complete privacy for sensitive recordings or personal videos, and no file size limits beyond your browser's memory. No watermarks are added and no signup is required.
Supported formats
Input: MP4 (H.264/H.265), WebM (VP8/VP9), MOV (QuickTime), AVI. Output: MP4 (H.264 + AAC). Works with videos from phones, screen recorders (OBS, Loom, ScreenPal), and cameras. Compatible with Chrome, Firefox, Safari, and Edge.
Compress videos for email and messaging
Many email providers and messaging apps have file size limits (typically 25 MB for email, 100 MB for Discord). Use this compressor to shrink your videos to fit these limits. The Medium preset with 720p resolution typically reduces file size by 60% or more while maintaining good visual quality. Remove the audio track for even smaller files when sound is not needed.