What will I receive?
MP4 to WEBM
The result is WebM with VP9 video and optional Opus audio, up to 720p/30 fps. Subtitles, attachments and capture metadata are removed; this is not a lossless remux.
Convert MP4 to WEBM online
Re-encode a short SDR MP4 clip as WebM with VP9 video and optional Opus audio.
Automatic deletion
InputMP4OutputWEBM
Step 1 of 3 · Files
Expires in 24 h- Files
- Format
- Result
Select MP4 files
From your phone, computer, or drag them here. · 50.0 MB per file · up to 1
The listed formats are accepted. Each file's structure is validated before conversion.
Conversion limits
What limits apply?
One video up to 50 MB and 2 minutes, SDR, maximum 4K/60 fps. Output up to 720p/30 fps. HDR and multiple video or audio tracks are not supported. Subtitles are removed.
Input and output expire automatically after the period shown in the converter. Download your result before then.
Practical guide
Convert MP4 to WebM for a destination requiring VP9 and Opus
This flow re-encodes a short MP4 as WebM with VP9 and optional Opus audio. It is not generic compression: use it when a website or application specifically requires WebM.
Check the input limits
One file up to 50 MB, two minutes, 4K and 60 fps is accepted. HDR, multiple video or audio tracks and structures that cannot be safely validated are rejected.
Understand normalized output
Video is limited to 1280 × 720 and 30 fps with VP9. Retained audio becomes stereo Opus, or it can be removed before starting.
Review what is not retained
Subtitles, attachments, chapters and metadata are removed. Only one video track and optional audio track are processed, so keep MP4 if it contains other elements.
Validate support and playback
Play the beginning, middle and end and check synchronization. WebM does not guarantee a smaller file, and some destinations prefer MP4.
For H.264/AAC compatibility use WebM to MP4; for a QuickTime source with the same target see MOV to WebM.
Frequently asked questions
What are the MP4 to WebM limits?
One file up to 50 MB and two minutes, input up to 4K/60 fps and output up to 720p/30 fps.
Which codecs does the WebM use?
Video is re-encoded as VP9 and retained audio as stereo Opus at 48 kHz.
Are subtitles and multiple tracks retained?
No. One video and optional audio track are processed; subtitles, attachments, chapters and metadata are removed.