Video Converter
Convert your videos to MP4 format with high quality and fast processing. All conversions happen locally in your browser.
100% private
Videos never leave your browser
Hardware-accelerated
WebCodecs + WebAssembly
8+ formats
MP4, WebM, MOV, MKV, AVI, WMV
Quality Settings
Drop videos here
or click to browse
FormatFuse's video converter uses Mediabunny and the browser's hardware-accelerated WebCodecs API to transcode video files directly on your device. That means even long 1080p clips can be converted without waiting for an upload-download round-trip, and the original file never leaves your machine.
Common jobs this tool handles well include swapping MOV recordings from an iPhone to MP4 for broader compatibility, re-encoding MKV to WebM for use on the open web, and bringing older AVI or WMV files into modern H.264 MP4. You can pick a quality preset (low / medium / high / ultra) to trade off size against fidelity.
Because conversion happens locally, there is no per-file size cap other than what your browser and device can hold in memory. Files stay private, there are no watermarks, and there is no queue.
Video Converter — Frequently Asked Questions
How do I convert MOV from my iPhone to MP4?
Drop the .mov file onto the page, pick MP4 as the output, and hit Convert. Your iPhone's H.264 stream is repackaged into an MP4 container that plays everywhere — Windows, Android, Gmail attachments, Slack, anywhere QuickTime isn't installed. No upload, no waiting.
Which video format should I use — MP4, WebM, or MOV?
MP4 (H.264) is the safest pick — it plays on every device, social platform, and messaging app. WebM (VP9 or AV1) is smaller at the same quality and great for the open web. MOV is what iPhones and Macs produce natively; convert to MP4 when sharing outside the Apple ecosystem.
Can I convert video without losing quality?
For lossless format changes that re-container without touching the video stream, pick the Ultra preset — it keeps the bitrate close to the source. True bit-for-bit lossless requires a remux (same codec, new container), which works when the source codec is already H.264 or VP9.
Can I convert multiple videos at once?
Yes — drop a folder of clips and every file is processed sequentially with the same quality settings. Outputs download individually as each one finishes.
What's the maximum video size I can convert?
There's no server-imposed limit because processing runs on your device. A modern desktop browser comfortably handles files up to several gigabytes. For very long 4K clips, a desktop is recommended over mobile to avoid running out of memory.
Is my video uploaded anywhere?
No. The conversion runs entirely in your browser using WebCodecs and WebAssembly. Your video files never leave your device or get uploaded to any server.
How do I convert MOV from my iPhone to MP4?
Drop the .mov file onto the page, pick MP4 as the output, and hit Convert. Your iPhone's H.264 stream is repackaged into an MP4 container that plays everywhere — Windows, Android, Gmail attachments, Slack, anywhere QuickTime isn't installed. No upload, no waiting.
Which video format should I use — MP4, WebM, or MOV?
MP4 (H.264) is the safest pick — it plays on every device, social platform, and messaging app. WebM (VP9 or AV1) is smaller at the same quality and great for the open web. MOV is what iPhones and Macs produce natively; convert to MP4 when sharing outside the Apple ecosystem.
Can I convert video without losing quality?
For lossless format changes that re-container without touching the video stream, pick the Ultra preset — it keeps the bitrate close to the source. True bit-for-bit lossless requires a remux (same codec, new container), which works when the source codec is already H.264 or VP9.
Can I convert multiple videos at once?
Yes — drop a folder of clips and every file is processed sequentially with the same quality settings. Outputs download individually as each one finishes.
What's the maximum video size I can convert?
There's no server-imposed limit because processing runs on your device. A modern desktop browser comfortably handles files up to several gigabytes. For very long 4K clips, a desktop is recommended over mobile to avoid running out of memory.
Is my video uploaded anywhere?
No. The conversion runs entirely in your browser using WebCodecs and WebAssembly. Your video files never leave your device or get uploaded to any server.