Bulk WebM to MP4 Converter
- Mediabunny-powered
- Client-side private
- H.264 MP4 output
- ZIP download
Use this WebM to MP4 converter to transcode WebM videos into H.264 MP4 files locally in a modern browser. The tool uses Mediabunny for in-browser conversion, keeps files on your device, and packages successful MP4 results into one ZIP.
A practical fit for screen recordings, browser captures, exported web video, and clips that need to play in editors, phones, messaging apps, and upload forms that expect MP4.
Video converter
WebM to MP4
Drag WebM files here
Or choose videos from your device and convert them locally in this tab.
Nothing uploads. Video encoding runs locally and may take about the length of each clip.
Use the WebM to MP4 converter in 3 steps
Add your WebM videos, run the local browser converter, and download every successful MP4 file in one ZIP. The workflow supports a single clip or a small batch.
- 1
Drag and drop WebM videos
Choose one or more .webm files from your device or drag them into the queue. Unsupported files are skipped so mixed batches are easier to clean up.
- 2
Convert with Mediabunny
Select Convert All to let Mediabunny transcode the primary WebM video track into H.264 MP4 directly in the browser.
- 3
Download one ZIP of MP4 files
When conversion finishes, successful MP4 files are packaged into one ZIP archive so you can save the whole batch in one click.
MP4 with H.264 video is the safest choice for playback outside the browser, including video editors, iPhones, Windows apps, and social platforms that reject WebM uploads. Browser support for the required in-browser media APIs can vary, especially for audio.
Frequently Asked Questions
The practical concerns are usually browser support, privacy, audio handling, output size, and what happens when a batch is mixed.
How do I convert WebM to MP4 online?
Add one or more WebM files, run Convert All, and let the browser process the video locally with Mediabunny. When conversion finishes, download the successful MP4 files together in one ZIP archive.
Does this WebM to MP4 converter upload my videos?
No. Conversion runs in your browser, so selected WebM files stay on your device instead of being uploaded to Toolsetta servers for processing.
Which browsers can convert WebM to MP4 locally?
A recent browser with the media APIs needed for local decoding and H.264 encoding is required. Chromium-based browsers currently have the best support for in-browser MP4 output.
Will the converted MP4 include audio?
Audio is included when the browser can decode the WebM audio track and encode AAC for the MP4 output. If that support is unavailable, the converter still exports the MP4 video track and marks the item as audio skipped.
Can I convert multiple WebM files at once?
Yes. The converter supports batch WebM to MP4 conversion. Add multiple WebM videos, convert the queue, and download all successful MP4 outputs in a single ZIP file.
Does converting WebM to MP4 reduce quality?
MP4 video is re-encoded from the WebM source, so output is not identical to the original. The converter chooses a practical H.264 bitrate for broad playback while keeping the workflow fully local.
Why use MP4 instead of WebM?
MP4 is useful when a video needs to play outside the browser, including video editors, iPhones and older devices, office tools, messaging apps, and upload forms that do not accept WebM files.
What happens if one WebM fails during conversion?
The queue shows file-level errors so you can identify the problem item. Successful conversions are still packaged for download, which is useful when only part of a batch needs to be retried.