Video Compressor — Reduce Video File Size Free Online, No Upload
Reduce video file size without leaving your browser — private, free, powered by FFmpeg.
Your computer does 100% of the processing — not a server, not the cloud.
FFmpeg runs directly inside your browser via WebAssembly. Your video file never leaves your device. No upload, no cloud processing — your own CPU handles everything.
- ✓Files stay on your computer — zero upload, zero cloud
- ✓Completely private — no account, no logging of your files
- ✓Works offline once the engine has loaded
- ⚠Speed depends entirely on your device. Your CPU and RAM do all the work.
- ⚠Very large files (1 GB+) may be slow or use significant memory.
Drop a video here or browse files
MP4 · WebM · MOV · AVI · MKV · WMV and more
Recommended: under 500 MB for reasonable compression times
About the Video Compressor
This tool uses FFmpeg's H.264 encoder with CRF (Constant Rate Factor) — the industry-standard approach to quality-controlled video compression. A higher CRF means smaller files at the cost of quality; a lower CRF preserves more detail. Output is always MP4 for maximum compatibility.
How presets work
High Quality → CRF 20 (near-lossless, minimal reduction)
Balanced → CRF 28 (default — best general-purpose choice)
Small File → CRF 35 (visible at full screen, fine for sharing)
Tiny → CRF 42 (heavy compression, use for previews only)
Related: Video Clipper to trim a video before compressing, Video Converter to change format, or Video to Audio to extract the audio track.
Frequently Asked Questions
Is the Video Compressor free?
Yes — completely free. No account, no subscription, and no file size limit.
Are my video files uploaded to a server?
No. FFmpeg runs inside your browser via WebAssembly. Your video never leaves your device.
Do I need an account?
No account, no login, and no signup required.
Which quality preset should I use?
Balanced (CRF 28) is the right starting point for most videos — it produces a noticeably smaller file with quality that looks fine at normal viewing sizes. High Quality (CRF 20) is for archiving or professional use. Small File and Tiny are for sharing where file size matters more than visual quality.
Why is compression slow?
H.264 encoding is CPU-intensive work done entirely on your device. WebAssembly runs single-threaded in most browsers, so speed depends on your processor. A 5-minute video typically takes 2–10 minutes.
Why is the compressed file sometimes larger than the original?
This happens with very short clips or already-compressed videos with low CRF settings. Try the Balanced or Small File preset, or check whether the original was already well-compressed.