Compress video files by up to 90% directly in your browser. Adjustable quality, resolution, and codec. 100% private — your video never leaves your device.
Drop your video here or click to browse
Supports MP4, WebM, MOV, AVI, MKV, FLV, WMV, 3GP
All compression happens locally using FFmpeg WebAssembly. No file is uploaded to any server. Open your browser's Developer Tools → Network tab to verify there are zero upload requests.
Upload Your Video
Drag & drop or browse. Supports MP4, WebM, MOV, AVI, MKV and more.
Adjust Settings
Choose CRF quality level, target resolution, codec, and audio bitrate.
Compress In-Browser
FFmpeg WASM re-encodes your video locally. Watch the progress bar.
Download & Compare
See before/after sizes and download your compressed video instantly.
Our free video compressor reduces video file sizes by 30–90% using FFmpeg (H.264/H.265) running entirely in your browser — no upload required. Adjust the CRF slider (18 = high quality, 28 = small file), choose a target resolution (1080p, 720p, 480p, 360p), and optionally reduce the audio bitrate. Lower CRF values preserve quality; higher values produce smaller files. Your video never leaves your device, making this the most private way to compress video online.
Upload your video by clicking the drop zone or dragging a file onto it. Supported formats include MP4, WebM, MOV, AVI, and MKV.
Adjust the compression settings: move the CRF slider lower for higher quality or higher for a smaller file. Optionally select a lower target resolution or reduce the audio bitrate.
Click "Compress Video" and wait for the in-browser FFmpeg engine to process your file. A progress bar shows real-time status.
Review the before/after file size comparison and download your compressed video. Your original file is never uploaded.
Our tool uses FFmpeg compiled to WebAssembly (WASM), which runs FFmpeg's powerful video encoding engine directly inside your browser. When you click compress, your video file is read into the browser's memory and re-encoded with the H.264 or H.265 codec at the CRF value and resolution you selected. No file is ever uploaded to a server — everything happens locally on your device.
No. This is the key privacy advantage of our video compressor. Your video file is processed entirely in your browser using WebAssembly. You can verify this by opening your browser's Developer Tools → Network tab during compression — you will not see any file upload requests. Your video never leaves your device.
CRF (Constant Rate Factor) controls the trade-off between quality and file size. CRF 18 is considered visually lossless (high quality, larger file). CRF 23 is the default balanced setting. CRF 28 produces a noticeably smaller file with acceptable quality for web sharing. For maximum compression, use CRF 30–32, though quality will degrade. A good starting point is CRF 26 for general use.
H.264 (AVC) is the most widely supported video codec — it plays on virtually every device and browser. H.265 (HEVC) achieves roughly 40% better compression than H.264 at the same visual quality, meaning smaller files. However, H.265 encoding is slower and some older devices may not play HEVC video. Use H.264 for maximum compatibility; use H.265 when you need the smallest possible file.
You can upload MP4, WebM, MOV, AVI, MKV, FLV, WMV, and 3GP files. The compressed output is always an MP4 (H.264 or H.265) or WebM file, which offers the best compatibility across browsers and devices. The original file extension is preserved when possible.
Typical compression results are 30–90% file size reduction depending on your settings. A 1080p video compressed to 720p at CRF 28 typically shrinks by 60–80%. Audio bitrate reduction adds another 5–10% savings. The exact ratio depends on the original codec, resolution, bitrate, and content complexity.
There is no artificial file size limit. However, since compression happens in your browser's memory, the practical limit depends on your device's available RAM. Files up to ~500 MB work well on most modern computers. Very large files (1 GB+) may cause the browser tab to crash if insufficient memory is available.
Video encoding is computationally intensive. Since FFmpeg runs as WebAssembly in your browser, it uses your device's CPU rather than a dedicated server. A 1-minute 1080p video typically takes 30–90 seconds to compress. H.265 encoding is roughly 2–3× slower than H.264. Lower CRF values (higher quality) also take longer. Larger videos naturally require more processing time.
Our tool uses FFmpeg compiled to WebAssembly (WASM), which runs FFmpeg's powerful video encoding engine directly inside your browser. When you click compress, your video file is read into the browser's memory and re-encoded with the H.264 or H.265 codec at the CRF value and resolution you selected. No file is ever uploaded to a server — everything happens locally on your device.
No. This is the key privacy advantage of our video compressor. Your video file is processed entirely in your browser using WebAssembly. You can verify this by opening your browser's Developer Tools → Network tab during compression — you will not see any file upload requests. Your video never leaves your device.
CRF (Constant Rate Factor) controls the trade-off between quality and file size. CRF 18 is considered visually lossless (high quality, larger file). CRF 23 is the default balanced setting. CRF 28 produces a noticeably smaller file with acceptable quality for web sharing. For maximum compression, use CRF 30–32, though quality will degrade. A good starting point is CRF 26 for general use.
H.264 (AVC) is the most widely supported video codec — it plays on virtually every device and browser. H.265 (HEVC) achieves roughly 40% better compression than H.264 at the same visual quality, meaning smaller files. However, H.265 encoding is slower and some older devices may not play HEVC video. Use H.264 for maximum compatibility; use H.265 when you need the smallest possible file.
You can upload MP4, WebM, MOV, AVI, MKV, FLV, WMV, and 3GP files. The compressed output is always an MP4 (H.264 or H.265) or WebM file, which offers the best compatibility across browsers and devices. The original file extension is preserved when possible.
Typical compression results are 30–90% file size reduction depending on your settings. A 1080p video compressed to 720p at CRF 28 typically shrinks by 60–80%. Audio bitrate reduction adds another 5–10% savings. The exact ratio depends on the original codec, resolution, bitrate, and content complexity.
There is no artificial file size limit. However, since compression happens in your browser's memory, the practical limit depends on your device's available RAM. Files up to ~500 MB work well on most modern computers. Very large files (1 GB+) may cause the browser tab to crash if insufficient memory is available.
Video encoding is computationally intensive. Since FFmpeg runs as WebAssembly in your browser, it uses your device's CPU rather than a dedicated server. A 1-minute 1080p video typically takes 30–90 seconds to compress. H.265 encoding is roughly 2–3× slower than H.264. Lower CRF values (higher quality) also take longer. Larger videos naturally require more processing time.