Convert WebM to MP4 Online for Free
Convert WebM to MP4 in your browser, with no upload.
Drop your WebM file here
or choose a local file or import from a URL
Choose a file to get started
How to Convert WebM to MP4
1. Choose your WebM
Drop in the original browser recording, or import a direct HTTPS link to the media file.
2. Set the resolution
Keep Original for small text and slide recordings. Choose 720p for a smaller phone preview.
3. Save your MP4
Select Convert WebM to MP4, preview the picture and sound, then download the file.
Which video and audio formats will the MP4 use?
What changes inside the file?
WebM and MP4 are containers. The container tells a player where to find the video, audio and timing information. A codec describes how the pictures or sounds were encoded. Screen capture software often writes VP8 or VP9 video and Opus audio into WebM. This WebM to MP4 converter targets H.264 video and AAC sound inside an MP4 container, a combination commonly used for presentations, phones and editing software.
That difference matters when a recording plays in a browser but another app refuses to import it. Changing the filename extension leaves the media data exactly as the recorder wrote it. When you convert WebM to MP4 here, the tool creates an actual MP4 and encodes the streams when their original codecs do not suit the output.
Does the conversion preserve every pixel?
When you convert WebM to MP4 with Original selected, the output keeps the source dimensions. If the picture needs re-encoding, fine texture and fast movement can look slightly different even at the same width and height. Compare the edge of a moving window, a thin line in a chart or a small number in a spreadsheet. A paused frame can tell you whether labels are legible; playing a few seconds shows whether detail breaks up during movement. Keep the WebM original for future edits.
What happens to audio and captions?
When you convert WebM to MP4, the output uses a main video stream and can include a soundtrack. A silent screen capture will remain silent. Captions that were part of the recorded picture stay visible because they are pixels in each frame. Selectable subtitles are separate tracks. Keep the original recording and any caption files if you intend to switch languages or turn captions on and off later.
When is an MP4 copy useful?
Insert a screen recording into a presentation
A presenter may be able to play a WebM by double-clicking it on a laptop, yet have trouble inserting the same file onto a slide. Convert WebM to MP4, keep the original resolution and insert the downloaded file into the presentation. Run the slideshow on the computer that will display it. Play a slide with narration through the intended speaker or headset and check that a click advances the slide when you expect it to.
Share a clip for review on a phone
For a short product demonstration, the recipient may only need to see which button was pressed and hear the explanation. A 720p MP4 can be a practical copy to try. For a portrait recording, inspect the whole frame on the phone and rotate the device to check orientation. If a reviewer needs to read a dense settings panel, send an original-resolution copy or crop the recording to the relevant area first.
Prepare a recording for an editor
If an editor asks you to convert WebM to MP4, first find out whether they need the entire session or just a selected passage. For an edit master, retain the original dimensions and keep the source alongside the MP4. For a short review, use the video trimmer to remove waiting time before export. Cutting a minute of an idle desktop often saves more space than making the action harder to see.
What affects file size and conversion time?
A WebM to MP4 conversion can produce a larger file. A screen recorder may have already used a low bitrate, especially when much of the picture is static. MP4 describes the file format and does not promise a particular number of megabytes. Compare the size of the finished download with the actual limit of the service that will receive it. Leave room for other attachments if several files are being sent together.
If the first export is too large, decide what you can give up. Removing an unnecessary opening preserves every remaining second at its current dimensions. Reducing resolution keeps the full running time but gives small objects less detail. For a strict attachment budget, use the video compressor to select a target in MB and check the finished size. Keep the more detailed copy if you also need a version for editing.
The time needed to convert WebM to MP4 depends on duration, frame size, codec support and available device memory. An hour of high-resolution video requires many more frames to be processed than a short browser demonstration. Keep the device awake and the tab open during export. If a recording is too demanding for the current device, try a shorter useful section first.
Where is my recording processed?
You can convert WebM to MP4 without sending a local recording to a media processing server. Your browser reads the selected file and creates the download on your device. This matters for a recording of a customer call or an internal dashboard. Review the exported picture and sound for anything you should remove before sharing the MP4 with someone else.
Importing from a URL adds one step: your browser must download the original from its host. A private dashboard URL or an expiring share link can open for you while still preventing a converter from reading the media. In that case, save the WebM locally and choose the file from your device. Very large inputs are limited by what the browser and device can handle.
Questions about converting WebM to MP4
Can I convert WebM to MP4 without losing quality?
Choose Original to retain the source dimensions. A typical VP8 or VP9 WebM still needs re-encoding to produce H.264 video. To judge the result, pause both files at the same frame and compare small text at the same zoom. Then play a section with fast movement. Keep the WebM as your editing master.
Why is the MP4 larger than my WebM?
A mostly static screen recording can already be very compact. Encoding the same frames as H.264 can use more bytes, even at the same resolution. If you need to fit a message limit, enter that limit in the video compressor after conversion. Compare the downloaded size with the space left after your other attachments.
Should I choose Original, 1080p or 720p for a screen recording?
Choose Original if someone needs to read menus, spreadsheet cells or code. A 720p copy is worth trying for a talking head or a quick phone preview. The height setting caps the output height: choosing 1080p for a 720p source will not add detail. Check the smallest label at the size your audience will actually see it.
How should I convert WebM to MP4 for PowerPoint?
Download the MP4, open the presentation and insert the saved video from your device. This tool targets H.264 video with AAC audio when sound is present. If you already inserted the WebM, replace that slide object with the exported file. Run the slideshow on the presentation computer and check both playback and sound.
Why can I hear the game but not my microphone in the MP4?
Play the original with headphones. If it has selectable audio tracks, switch between them and listen to the same sentence. Game sound and microphone audio may be on separate tracks. This page exports one soundtrack. To include both, mix the two tracks in an editor before export. If the original never captured the microphone, conversion cannot recover it.
Can I convert WebM to MP4 and keep a transparent background?
The H.264 MP4 produced here does not preserve an alpha channel. For a logo or overlay that must reveal the layer underneath, keep the transparent WebM. If the final background is already decided, composite the overlay onto that background in your editor, then export the finished scene as MP4.
Will my captions still appear if I convert WebM to MP4?
Look for the subtitle switch in your source player. If the words stay visible when subtitles are off, they are part of the picture and will remain visible. If they disappear, keep the caption file or extract the embedded text track separately. This page has no subtitle-selection control.
Can I convert WebM to MP4 without cropping a vertical recording?
Yes. Choose Original to keep the recording’s dimensions. The resolution control changes the output height while preserving the aspect ratio. If a social app displays black bars, first check its preview setting. Use the video cropper only when you want to remove part of the picture to fill a different shape.
My WebM plays from the beginning but I can’t seek. Is it damaged?
A browser recording can lack the duration or seek information a player expects. Try playing the original through the point you need. If it plays, export a copy and test seeking near the middle and end of the MP4. If every player stops at the same point, retrieve the complete recording from the recorder before trying again.
Why does a link open in my browser but fail to import?
A viewing page, login screen or share link can load in a tab without giving the converter access to the media bytes. URL import needs a direct HTTPS file link whose host allows browser access. Download the WebM through its original site, then select that local file here.
Can I convert WebM to MP4 if my recording is over 500 MB?
There is no fixed 500 MB input cutoff. A large recording can still exhaust browser memory while the output is being assembled. Keep the tab open and the device awake. If export repeatedly stops, close memory-heavy apps, try a shorter section, or use a desktop encoder for the full session.
Is my private screen recording uploaded when I convert it?
With a file chosen from your device, media processing happens in the browser. URL import downloads the source from its host. Download the finished MP4 before closing the tab, and check the picture for private notifications or account details before sending it to another person.