WebM to MP4 screen recordings that play anywhere.
To convert WebM to MP4, choose the screen recording or downloaded video and click convert. The VP8 or VP9 video becomes H.264 and the Opus audio becomes AAC, the pair that plays on iPhone, on WhatsApp and in any editor. You pick the quality and follow the progress to the end.
Free, no sign-upEverything fits MP4: we only swap the container. It takes seconds and the quality stays identical.
This video is HDR. When it is re-encoded, colors may look different from the original.
For Windows PCs without the HEVC extension, older TVs and iPhones or Macs without AV1. Takes longer.
How to turn a WebM into an MP4
- 01
Choose the .webm
Drag the file onto the area above or pick it from your device. We show the video codec, the audio codec, the resolution and the length.
- 02
Pick the quality
High for screen recordings with small text or for editing; balanced for sending and posting; smaller file for messaging apps.
- 03
Convert and download
The button shows the percentage and time left. At the end, watch the preview and download the .mp4 with the same name as the .webm.
Where do WebM files come from?
WebM is an open format made for video on the web. Inside, it carries VP8, VP9 or AV1 video and Opus or Vorbis audio. Browsers record in this format natively, which is why it shows up in screen recorders that run in a tab, recording extensions, online meeting and class tools, and videos downloaded from some sites.
The trouble starts when the file leaves the web. The iPhone Photos app and QuickTime don't open WebM, WhatsApp won't take it as a video and many editors ask for MP4. Converting fixes it in one go: an MP4 with H.264 and AAC plays on phones, computers, TVs, editors and social networks.
| Where the WebM came from | What's usually inside | What we do |
|---|---|---|
| Screen recorder in a tab | VP8 or VP9 + Opus | Re-encode to H.264 + AAC |
| Recording extension | VP8 or VP9 + Opus | Re-encode to H.264 + AAC |
| Video downloaded from the web | VP9 + Opus | Re-encode to H.264 + AAC |
| WebM with AV1 | AV1 + Opus | Copy video, audio becomes AAC |
Does renaming .webm to .mp4 work?
No. Changing the extension only changes the name: inside, the file is still VP9 with Opus, and the app that rejected the WebM still rejects it. Some players do play it, because they look at the content and ignore the name, but the iPhone, WhatsApp and editors don't.
A real conversion re-encodes the video: every VP8 or VP9 frame is decoded and compressed again as H.264, and the Opus audio is rewritten as AAC. That takes longer than a copy and depends on the length and the resolution; the button shows the percentage and time left. The timing of every frame is kept, so sound stays in sync with the picture, even in screen recordings with a variable frame rate.
Which quality should I pick for a screen recording?
Screen recordings have small text, icons and thin edges, which suffer more from compression than a face does. For tutorials, lessons and software demos, use high quality. For a recorded meeting that will only be reviewed, balanced is usually enough. The smaller file option is for sending by message or email, when size matters more than sharpness.
In every option the bitrate is adjusted to the source, so the MP4 doesn't end up much bigger than the WebM. At 1080p and 30 fps that is close to 7.5, 4.7 or 2.8 Mb/s of video, with AAC audio at 192, 160 or 128 kb/s.
- A WebM with AV1 has its video copied without re-encoding; only the Opus audio is rewritten as AAC.
- If the WebM is HDR, we warn you before converting that colors may shift.
- Recordings without sound convert too: the MP4 comes out with picture only.
More than WebM to MP4. Your recording becomes text, chapters and clips.
See also
Frequently asked questions
How do I convert WebM to MP4 for free?
Choose the .webm file on this page, pick the quality and click convert WebM to MP4. The video becomes H.264 and the audio becomes AAC. It's free, with no sign-up, no watermark and no usage limit.
Does converting WebM to MP4 lose quality?
There is a new compression, because VP8 and VP9 have to become H.264. At high quality the difference is hard to see, even in screen recording text. The exception is a WebM with AV1: the video is copied without recompressing and stays identical.
Why won't WhatsApp or my iPhone open my WebM?
Because they don't accept VP8, VP9 or Opus as everyday video. They expect MP4 with H.264 or HEVC and AAC audio. Once converted, the file opens in the iPhone Photos app and goes through WhatsApp as a normal video.
How long does WebM to MP4 take?
It depends on the length and the resolution, because the video is re-encoded. A few minutes of 1080p screen recording usually takes a few minutes. The button shows the percentage and time left while it converts.
Will the audio go out of sync after converting?
No. We keep the timing of every frame from the original, so speech matches the picture from start to finish, even when the screen recording has a variable frame rate.
Can I convert WebM to MP3, audio only?
Yes, with another tool: the WebM to MP3 converter takes just the sound from the recording and gives you an MP3 ready to play or send.
Your screen recording as text and chapters. No converting first.
Upload the WebM as is. We transcribe every word, split it by topic and find the best moments to turn into clips.
See the result on your own recording before adding a card.