Our Video Converter uses WebAssembly technology to process compatible files locally in your browser. Your video does not need to be uploaded to a conversion server. Choose MP4, WebM, or MKV as the target format, adjust the available resolution settings, and download the converted file. Conversion speed and maximum file size depend on your device memory and processing power.
Privacy Protected
Convert Video Files Online
Fast, free, and 100% private online video converter. Convert videos between MP4, WebM, and MKV formats entirely in your browser. No uploads required.
Share Tool
Select files or drag & drop here
Processed 100% locally in your browser. Your files never touch an external server.
Choose File to Begin
100% Client-Side Privacy•No File Size Limits•Free Forever
About Convert Video Files Online
FusioFiles 100% Client-Side Privacy Guarantee
Your files and data never leave your browser — processed directly on your device.
Zero Server UploadsExecution occurs entirely in browser memory via WebAssembly and HTML5 Canvas.
HIPAA & GDPR ReadySafe for confidential tax forms, medical records, financial sheets, and legal contracts.
Zero Cloud LatencyInstant results with no upload delays, server queues, or third-party tracking.
Automatic RAM PurgeBuffers and caches are automatically wiped clean the instant you close the tab.
1
Select Video
Choose the video file you want to convert.
2
Choose Format
Pick your target format and resolution settings.
3
Convert & Download
Click 'Start Conversion' and save your file locally.
Key Features
100% Private
Zero server uploads. Your videos stay on your device.
Fast Conversion
Powered by ffmpeg.wasm for near-native performance.
Multiple Formats
Convert between MP4, WebM, and MKV with ease.
Frequently Asked Questions
Yes, we use ffmpeg.wasm to process the video entirely in your browser.
The only limit is your device's memory. We recommend files under 200MB.
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