How to Compress a WebM Video Online
Follow these three simple steps to compress a WebM video. No software installation required.
Select a WebM Video
Choose one WebM file 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, compare the original and output file sizes, and download the compressed video.
How Does the WebM Compressor Work?
WebM video compression reduces file size by removing redundant information during re-encoding. CompressFly uses the H.264 codec to retain high visual quality while reducing the amount of data stored in the video. Quality and optional resolution settings control the balance between output size and visual detail.
CompressFly handles WebM compression with modern browser technology. No files are sent to a server: everything is processed locally in your browser. Smart video compression makes reducing WebM file size simple and free, with no signup required.
What "processed in your browser" means
- Your WebM file 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.
WebM Compression FAQs
How do I compress a WebM video online?
Use this online WebM compressor to reduce WebM video file size in three steps: 1. Select one WebM video from your device. 2. Choose the output quality and optional resolution. 3. Compress the video and download the result.
How can I compress a WebM video without losing quality?
Choose the High quality preset to retain as much visual detail as possible. Keep the original resolution when reducing the dimensions is not necessary.
How does the WebM compressor reduce file size?
The compressor re-encodes the WebM 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. Everything runs locally in your browser.
How much smaller can a WebM video get?
Some high-bitrate WebM videos can become 50–90% smaller, but this is not guaranteed. WebM files that are already optimized for the web may shrink very little or produce a larger result after re-encoding. The result depends on the source bitrate, resolution, motion, and selected settings.
Is there a WebM file size limit, and is my video uploaded?
Your WebM video is processed locally in your browser and is 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.