Convert WebM to MP4
Convert WebM screen recordings and downloads to MP4 in your browser, re-encoded as H.264 so they play in PowerPoint, on iPhones and in most editors. No upload.
Process locally
Files stay in this browser session. Closing or clearing releases them.
Choose files
MP4, MOV, WebM, MKV, up to 5
Drop files here, or
Adjust settings
Optional: Output format, Largest height, Sound and more
Run
Processes in this browser; cancel at any time
About this task
Browser screen recorders and many web downloads save WebM, with VP8 or VP9 video and Opus sound. PowerPoint, iMovie and many social sites expect MP4 instead, so this page opens the video converter set to MP4 with H.264 video.
Every frame is decoded and encoded again, because WebM’s codecs do not play widely inside an MP4. The sound becomes AAC where your browser has an AAC encoder; elsewhere, such as in Firefox, the Opus sound is kept, which some players do not support. Up to 5 videos, 80 MB in total, are converted in your browser.
How to do it
- Choose or drop up to 5 WebM videos, 80 MB in total.
- Keep “Output format” on “MP4 (H.264 + AAC)”. Choose Remove under “Sound” for a silent clip.
- Select Run; long or high-resolution recordings take a while to re-encode.
- Preview the MP4 and download it.
Common questions
Can I cut the recording at the same time?
Yes. Enter a start and end time in seconds or m:ss, such as 0:05 and 2:30, to drop the setup at the beginning and the end of a screen recording in the same run.
Will the MP4 play in PowerPoint and on an iPhone?
Yes when it has H.264 video and AAC sound. In Firefox the sound stays Opus, which PowerPoint and iPhones may not play, so use Chrome, Edge or Safari on Windows or macOS for those.
Why does a long recording fail to convert?
Each run may take at most 2 minutes, and re-encoding a long, high-resolution screen recording takes longer than that. Convert it in parts with the start and end times, or choose 720p under “Largest height”.
Other settings and related tasks
Need other settings? Open the full Convert video format tool.