How to convert WebM to MP4
- 1
Click Choose files or drop one or more .webm files into the box.
- 2
Click Convert. When needed, the video is re-encoded to H.264 with AAC audio, the most compatible MP4 combination.
- 3
Each MP4 downloads when it's ready; for several files use Download all (ZIP).
Where WebM files come from
WebM is the open video format of the web. You’ll typically meet it when:
- Recording your screen with browser-based tools, extensions or online meeting recorders.
- Saving a video from a website or a social platform’s download feature.
- Exporting from web apps that create animations, presentations or clips.
Browsers play WebM perfectly, but outside the browser it’s another story: older iPhones and QuickTime, PowerPoint, many video editors, smart TVs and course platforms may refuse it.
WebM vs MP4
| WebM | MP4 (H.264/AAC) | |
|---|---|---|
| Video codecs | VP8, VP9, AV1 | H.264 (most common) |
| Audio codecs | Opus, Vorbis | AAC |
| Plays in browsers | Yes | Yes |
| Plays on iPhone, TVs, editors | Not always | Practically everywhere |
Speed and quality
Because WebM and MP4 use different codecs, the conversion re-encodes the video to H.264 — the same work a desktop video converter would do, but on your device instead of a server. For a short screen recording this takes moments; for a long 1080p recording expect it to take a while. A laptop or desktop is recommended for long files; keep the tab open until the download starts.
Common problems
- It’s taking a long time. Re-encoding a long, high-resolution recording is heavy work. Trim it first or use a computer.
- The recording has no sound. Many screen recorders don’t capture audio unless you enable it; the MP4 will be silent as well.
- The original is choppy. Converting keeps the frames that were recorded; it can’t add frames a struggling recorder dropped.
Tips
- Too big after conversion? Trim the dead time with Trim video or shrink it with Compress video, which also outputs MP4 from WebM directly.
- Only need the sound of a meeting? MP4 to MP3 accepts WebM files and is much faster than converting the video.
- Other formats: MOV to MP4 for iPhone videos, MKV to MP4 for MKV files.
No upload, no account and no watermark: your screen recordings — which often show emails, documents or dashboards — never leave your computer.