How to Convert Video Online
Drop your video file above and select the target format: MP4, WebM, or MKV. The tool decodes the original file, re-encodes it with the appropriate codec, and gives you a download. The entire conversion happens in your browser. Nothing is uploaded anywhere.
This is useful when you have a WebM from a screen recording that needs to be MP4 for sharing, or an MKV from OBS that needs to play on an iPhone. If the file is also too large, combine this with the video compressor for format conversion and size reduction in one workflow.
MP4 vs WebM vs MKV: Format Differences
MP4 (H.264 + AAC) is the universal format. Every device, browser, and platform plays it. Choose MP4 when compatibility is the priority. WebM (VP8/VP9 + Opus) is Google’s open format, optimized for web embedding. It typically produces smaller files at comparable quality.
MKV is a flexible container that supports virtually any codec. It is popular for archival and editing but lacks native playback support on Apple devices and many web players. For social media, email, or client delivery, MP4 is almost always the right choice.
Why Convert Video in the Browser?
Upload-based converters send your entire video to a remote server, which is slow for large files and risky for confidential content. This converter runs locally on your GPU via WebCodecs. There are no file size limits imposed by a server, and your files remain private.
After converting, you can trim the output or extract the audio track. For professional captioning and subtitle workflows, explore Velocaption. Browse all free tools on the tools page.
