How to Compress a Video Online
Follow these three simple steps to compress a video. No software installation required.
Select a Video
Choose one MP4, MOV, WebM, AVI, MKV, or M4V video from your device.
Choose Quality and Resolution
Select a video quality level and keep the original resolution or choose a lower output resolution.
Compress and Download
Start compression, review the original and output file sizes, and download the compressed video.
How Does the Video Compressor Work?
Video compression reduces the amount of data in a video by removing redundant information. CompressFly uses the H.264 codec to retain high visual quality while reducing file size. The selected quality level and optional output resolution determine the balance between size and visual detail.
CompressFly handles video compression with modern browser technology. No files are sent to a server: everything is processed locally in your browser. Smart video compression makes reducing file sizes simple and free, with no signup required.
What "processed in your browser" means
- Your video is not uploaded to a server.
- Compression runs locally on your device.
- The compressed video is created in your browser and downloaded directly to your device.
Video Compression FAQs
How do I compress a video online?
Use this online video compressor to reduce video file size in three steps: 1. Select one video from your device. 2. Choose a quality level and optional output resolution. 3. Start compression and download the compressed video.
What video formats can I compress?
The video compressor accepts MP4, MOV, WebM, AVI, MKV, and M4V files.
How can I compress a video without losing quality?
Choose the High quality preset to retain as much visual detail as possible. It usually creates a larger file than the Medium or Low presets.
How does video compression work here?
The compressor re-encodes the video with H.264 at a lower effective bitrate. Bitrate is the main factor that determines file size, while lowering the resolution—for example, from 4K to 1080p—can reduce it further by giving the encoder fewer pixels to process. Everything runs locally in your browser.
How much smaller can a compressed video get?
Some high-bitrate phone videos and screen recordings can become 50–90% smaller. For example, a 200 MB source may sometimes fall to around 20–40 MB, but this is not guaranteed. Videos already optimized for the web usually shrink less.
Is there a file size limit, and are my videos uploaded?
Your videos are processed locally in your browser and are not uploaded to a server, so there is no server upload limit. The practical limit depends on your device's available memory and processing power, as well as the video's length and resolution.