MP4 to WebM Converter
Convert MP4 to WebM online for free: nothing to install, no watermark, files encrypted in transit and deleted automatically after conversion.
Advanced options
Drag & drop your MP4 file here, or
How to convert MP4 to WebM in 3 steps
- 1
Upload your MP4 file
Drag and drop or select the MP4 file you want to convert.
- 2
Choose WebM as output
The output format is pre-selected for you — just confirm and start the conversion.
- 3
Download your file
Once processing finishes, download your converted WebM file instantly.
Converting MP4 to WebM: what to know
When you need it
WebM is the open video format designed for the web: it streams well in an HTML video element and usually gives smaller files than MP4 at similar quality, which helps page speed on your own site.
What to expect
The video is re-encoded to VP9 with Opus audio. VP9 encoding is slower than H.264, so long videos take a while. All current browsers play WebM, though older Apple devices may not.
Tip: Keep the MP4 as well: WebM is great on your website, but MP4 is still the safer choice for sending to people and uploading to social networks.
MP4 vs WebM: what is the difference?
| MP4 | WebM | |
|---|---|---|
| Full name | MPEG-4 Part 14 | WebM |
| Type | Video container | Video container |
| Compression | Depends on the codec | Lossy |
| Developed by | MPEG (ISO/IEC) | |
| File extension | .mp4 | .webm |
What is MP4?
MP4 is the most widely used video container. It usually carries H.264 or H.265 video with AAC audio, and it plays on practically every phone, browser, smart TV and editing program, which makes it the safest choice for sharing and uploading.
What is WebM?
WebM is an open, royalty-free video format backed by Google and designed for the web. It uses VP8, VP9 or AV1 video with Opus or Vorbis audio, plays natively in modern browsers and keeps files small, though some editors and Apple devices handle it poorly.
Tips for converting MP4 to WebM
- Check the length and resolution of your MP4 file first: long 4K videos take several minutes to process and may exceed the 50MB free limit.
- If you only need the soundtrack, pick an audio format such as MP3 instead of WebM — the file will be much smaller.
- Keep the original video until you have checked the converted file plays correctly on the device you want to use.
- Subtitles and extra audio tracks are not always carried over between containers, so check them after converting.
Frequently asked questions
- How do I convert MP4 to WebM online?
- Upload your MP4 file above, select WebM as the output format, and click Convert. ConvertFastHub processes the file in the cloud and gives you a download link — no software installation required.
- Is it free to convert MP4 to WebM?
- Yes. Free accounts get 10 conversions every 24 hours with files up to 50MB. For unlimited conversions, larger files up to 1.5GB, and priority processing, upgrade to ConvertFastHub Pro.
- Is my file safe when I convert it?
- Files travel over an encrypted connection, are scanned automatically for malware (files up to 200 MB), are processed in an isolated worker and are deleted automatically: after 1 hour without an account, 24 hours with a free account, or 7 days with Pro.
- Can I convert MP4 to WebM on my phone?
- Yes. The converter runs in the browser and the work happens on our servers, so it works the same on Android, iPhone, tablets and computers — there is no app to install.
- Do I need an account?
- No. You can convert without signing up; results are then kept for 1 hour. A free account keeps them for 24 hours and shows your conversion history.