MP4 to WEBM converter
Convert MP4 to WEBM in seconds, free and unlimited. No upload, no sign-up, no watermark: your video never leaves your device.
Last updated
Quick answer: To convert MP4 to WEBM, add the MP4 file to the iHateFiles MP4 to WEBM converter and press Convert. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. An open, royalty-free format that browsers play natively.
Should you convert MP4 to WEBM?
Do this when something specifically needs WEBM. The picture is re-encoded, so it costs a little quality; if all you need is a file that plays everywhere, MP4 is usually the better target.
The picture is re-encoded
An MP4 usually holds H.264 or H.265 video with AAC sound. This writes VP8 video with Vorbis sound into the WEBM. Both sides are compressed with loss, so this is a second generation: leave the quality at its default or higher, because the encoder is working from MP4 artefacts rather than the original.
Extra tracks may not survive
An MP4 can carry several audio tracks and subtitle tracks. WEBM is more limited, so this conversion keeps the main video and the first audio track. If you need the subtitles, save them first with Extract Subtitles.
Where the WEBM will play
WEBM plays on every modern browser and Android, but not QuickTime or older iPhones.
MP4 and WEBM side by side
| MP4 | WEBM | |
|---|---|---|
| Inside the file | H.264 or H.265 video with AAC sound | VP8 video with Vorbis sound |
| Compression | Lossy | Lossy |
| Carries sound | Yes | Yes |
| Plays on | every phone, laptop, TV, browser and messaging app | every modern browser and Android, but not QuickTime or older iPhones |
| Here | Read and write | Read and write |
What usually goes wrong
About the MP4. Two MP4 files can behave completely differently depending on the codecs inside. A file that will not play is usually an unusual codec in an ordinary container, not a broken file.
About the WEBM. A browser screen recording is usually a WEBM with a broken duration, so players show it as zero seconds or refuse to seek. Converting it to MP4 rewrites the header and fixes the seeking.
How to convert MP4 to WEBM
- Add your MP4 file. It is read from your disk and stays there.
- Check the settings. The output format is already set to WEBM.
- Press convert and the WEBM file is saved back to your device.
Questions
How do I convert MP4 to WEBM?
Open this page, add your MP4 file, and press convert. The file is decoded and re-encoded by your own browser and saved back to your device. Nothing is uploaded.
Is this MP4 to WEBM converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Will converting to WEBM lose quality?
WEBM is a lossy format, so some detail is discarded. The quality control on this page decides how much. The default is set high enough that most people cannot see the difference.
Can I convert several MP4 files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.