WEBM to MP4 Converter
Convert WEBM to MP4 online for free. Fast, secure, and high-quality conversion with no sign-up or software required.
Maximum file size is 1GB
How it works
Three steps to your converted file
Everything happens in your browser tab - upload, pick a format, download. The heavy lifting runs on our servers.
Upload your file
Drag and drop, click to browse, or paste a URL. Batches take up to 20 files at once - 230+ input formats across video, audio, image, document, and archive types.
Choose an output format
Pick from over a hundred output formats. Filter by category or search by name - every option is open to everyone, no account needed.
Convert & download
Hit Convert and grab your download link moments later. Originals are erased when the job completes; results are cleared within about an hour.
What is a WebM file?
WebM is an open, royalty-free audiovisual media file format sponsored by Google, derived from the Matroska (MKV) container. Designed specifically for the HTML5 video element, it restricts streams to specific codecs: video is compressed using VP8, VP9, or AV1, while audio utilizes Vorbis or Opus. The format structure is defined by a subset of the Matroska specifications, prioritizing efficiency for web streaming and low computational overhead for decoding in browser environments.
How to open a WebM file
As a native HTML5 format, WebM files open directly in modern web browsers including Google Chrome, Mozilla Firefox, Microsoft Edge, and Opera without plugins. For offline playback, cross-platform media players like VLC media player, MPV, and FFmpeg-based tools provide full support. Windows Media Player may require the installation of WebM Media Foundation Components to render these files.
WebM Technical Info
- Full Name
- Web Media
- Developed By
- Initial Release
- 2010
- MIME Type
- video/webm
What is an MP4 file?
MPEG-4 Part 14 (MP4) is a digital multimedia container format defined by ISO/IEC 14496-14. Based directly on the QuickTime File Format (QTFF), it allows for streaming over the Internet and is the global standard for video compatibility. An MP4 file can store video streams (encoded with H.264/AVC, H.265/HEVC, or MPEG-4 Visual), audio streams (typically AAC or MP3), subtitles, and still images. It utilizes object-oriented structures specifically designed to support initial object descriptors (IOD) and other MPEG features.
How to open an MP4 file
MP4 is the most widely supported video format in existence. It opens natively on virtually all modern operating systems including Windows (via Movies & TV or Windows Media Player), macOS (QuickTime), Android, and iOS. Web browsers (Chrome, Firefox, Safari) also support native MP4 playback via the HTML5 video tag. No external software is generally required, though VLC Media Player is useful for MP4 files containing obscure codecs.
MP4 Technical Info
- Full Name
- MPEG-4 Part 14
- Developed By
- ISO / IEC
- Initial Release
- 2001
- MIME Type
- video/mp4
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Why RunConvert
The fastest way to convert any file
Purpose-built for speed, privacy, and breadth of format support.
Convert WEBM to MP4 in seconds
Every WEBM to MP4 conversion runs on our servers, so your device stays fast and the output quality stays intact.
Fast, cloud-powered
No queue, no waiting. Files are processed on high-performance servers and returned in seconds, even for large files.
Secure & private
Encrypted in transit and never shared with anyone. Uploads are erased the moment your job completes, and results shortly after.
Free - no account needed
Convert without creating an account - no credit card, no trial clock. Sign in only if you want history and higher daily limits.
Developer API
Convert WEBM to MP4 via API
Automate WEBM to MP4 conversions in three steps: create a job, upload your file, then poll for the result.
# 1. Create job
curl -X POST https://api.runconvert.com/v3/jobs \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"tag": "webm-to-mp4",
"tasks": {
"upload-file": {
"operation": "import/upload"
},
"convert": {
"operation": "convert",
"input": "upload-file",
"output_format": "mp4"
},
"export-result": {
"operation": "export/url",
"input": "convert"
}
}
}'
# 2. Upload your file (use upload_url from the response)
curl -X PUT "$UPLOAD_URL" --upload-file input.webm
# 3. Poll for result
curl https://api.runconvert.com/v3/jobs/$JOB_ID?include=tasks \
-H "Authorization: Bearer YOUR_API_KEY"Replace YOUR_API_KEY with your RunConvert API key. Get your free API key at runconvert.com/api.
FAQ
Frequently asked questions
Common questions about converting WEBM to MP4 with RunConvert.
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