Smart Video Compression or a Custom MB Size
Smart compression is the quick option when you simply want a noticeably smaller video without working out technical settings. It reads the original file size, duration, bitrate, and resolution, then chooses a practical resolution and bitrate that balance speed, clarity, and savings in one encoding pass. When a website gives you a strict upload limit, switch to target-size mode instead. You can choose 20MB, 25MB, 50MB, or 100MB, enter a custom value, and let the tool reserve a small safety margin so the result is less likely to be rejected.
Private Browser Video Compression
The selected video is processed locally in your browser with FFmpeg WebAssembly. It is not uploaded to this site, stored on our server, or sent through a third-party compression API. The first use downloads the video engine, but that download contains program code rather than your file; the browser can normally reuse it from cache later. Local processing is useful for family clips, work recordings, private messages, and any video you would rather not hand to an upload service. Keep the page open until processing and download are complete.
Choose MP4, WebM, MOV, MKV, or AVI Output
You can open common inputs including MP4, MOV, WebM, MKV, AVI, M4V, MPEG, and MPG. Output is available as MP4, WebM, MOV, MKV, or AVI. MP4 is usually the safest choice for phones, chat apps, forms, presentation software, and social platforms. WebM works well for websites and modern browsers. MOV suits QuickTime workflows, MKV is useful when a flexible container is accepted, and AVI supports older software. Changing the container does not guarantee a smaller file by itself, so the compressor also adjusts bitrate and, when appropriate, resolution.
Automatic Resolution Protects Usable Quality
A very small target cannot hold the same detail at every video length. The automatic resolution option estimates the available video bitrate after reserving space for audio, then lowers the resolution only when keeping the original dimensions would create a blurry result. A short clip may stay at 1080p or 720p, while a long recording aimed at a small MB limit may need 480p, 360p, or 240p. You can override the recommendation, but the page warns when the chosen resolution is unrealistic for the available bitrate instead of pretending that every combination will look good.
Use Multiple CPU Cores on a Computer
Video encoding uses the CPU and memory of the device in front of you. When the browser supports cross-origin isolation and SharedArrayBuffer, the tool detects the available logical cores and enables multi-core FFmpeg. Browser WebAssembly is less stable than native desktop FFmpeg at high thread counts, so encoding is capped at four cores: dual-core devices use two, while four-core and larger devices use four. This avoids the deadlocks and extreme memory use that can appear with larger pools. For long, high-resolution, or near-1GB videos, use a desktop or laptop, close heavy tabs, and avoid letting the device sleep.
