Convert MP4 to WebM Online for Free
Turn an MP4 into a WebM for your website, app or video player.
Drop your MP4 video here
or choose a local file or import from a URL
Choose a file to get started
How to convert MP4 to WebM
1. Select your MP4
Choose the video you want visitors to see. Keep the original around if your site will offer an MP4 fallback. Check the running time so both files show the same edit.
2. Choose the resolution
Start with Original. If the video will occupy a small product card, try a lower resolution and see whether the button labels and pointer movements still read at the actual display size.
3. Save the WebM
Select Convert MP4 to WebM and download the result. Play the saved file, then test it through the page or application that will deliver it to viewers.
How to serve a WebM alongside the original MP4
A product demo might play perfectly when you open the WebM from Downloads, yet still use the MP4 on your website. The converter creates a media file. Your site decides which file to offer. Upload the new WebM, keep a working link to the MP4 if you need a fallback, and point your video player at the intended sources. Give the two files distinct extensions and use the appropriate media type for each one.
<video controls playsinline>
<source src="demo.webm" type="video/webm">
<source src="demo.mp4" type="video/mp4">
</video>| What you observe | What to check |
|---|---|
| The browser requests the MP4 first | Inspect the source order in the live player. Put the WebM first if it is the preferred candidate. |
| The WebM address opens a download or an HTML error page | Check the published file path, permissions and response type. A WebM video should be served as video/webm. |
| The player works after a click but does not start on page load | Check autoplay settings and whether the element is muted. Converting a file does not grant autoplay permission. |
| The picture plays but a narrated demo is silent | Check the player’s mute state, then play the saved file outside the page to verify the soundtrack. |
When you convert MP4 to WebM for a site that offers several sources, the browser normally chooses a source it expects it can play. It does not compare the sizes of every alternative and automatically pick the smallest. Open the browser’s network panel and reload the published page. The media request tells you which file visitors with that browser are actually getting. Test another device if the clip will be important to a mobile workflow.
How to convert MP4 to WebM for a smaller page asset
Compare files from the same edit. A fifteen-second preview should not be judged against an entire two-minute product tour. First compare the actual byte sizes, then look at the WebM in the space where it will appear. A moving pointer, a small price label and a fading menu can each reveal changes that are hard to see in a still image. A lower resolution is useful only if the actions that matter remain understandable.
If you convert MP4 to WebM from an already efficient MP4, the WebM can end up larger. Duration, resolution, movement and the encoders all influence size. This page lets you select a resolution. It does not offer a target byte count or a manual bitrate. If the preview only needs to show one interaction, keeping that interaction and trimming the surrounding pauses can help more than reducing every frame.
The browser processing path can produce VP9 video, while the alternate encoding path uses VP8. A readable audio track is targeted to Opus. WebM names the container, so its extension alone does not identify the video codec. If a publishing tool insists on VP9 specifically, inspect the actual downloaded file before submitting it. You cannot force an individual codec with the resolution control.
Convert MP4 to WebM for a spoken demo or a silent loop
For a spoken walkthrough, keep playback controls available and listen to a sentence with a visible action. Someone might say “open settings” and then choose a button. Check those two moments together near the beginning and after the longest pause. If the source contains alternate languages or separate subtitle files, prepare the track you want to deliver; this page has no language picker and does not import companion captions.
For a decorative loop, decide what should happen before the video starts and after its last frame. Muting the player prevents sound during that playback, but does not remove the audio from the downloaded file. Repetition, inline playback and a poster image are also player settings. After you convert MP4 to WebM, check the start and end together on the page. An abrupt jump back to the first frame may call for a different cut, not another change of container.
Frequently asked questions about MP4 to WebM conversion
Can I convert MP4 to WebM online for free without signing up?
Yes. Open one MP4 on your device, choose a resolution and download the result from your browser. Keep the tab open until you have saved the WebM.
Will the file get smaller if I convert MP4 to WebM?
There is no fixed saving. Compare the downloaded file with the original at the same duration. If small text remains readable, you can try a lower resolution or create a shorter version that shows just the interaction you need.
Which video and audio codecs are used?
The converter uses VP9 or VP8 for video depending on the available processing path. A readable source soundtrack can be encoded as Opus. Check the output’s media information if your destination requires a particular combination.
Can I convert MP4 to WebM just by renaming it?
Changing the extension leaves the original MP4 structure and streams in place. Export a new WebM so a server, browser or upload form that expects that container receives an actual WebM file.
Can I convert MP4 to WebM without changing the resolution?
Choose Original. That keeps the source dimensions as the starting point, although video encoding can still change fine detail. Compare the two recordings at the same display size and with the same amount of motion.
Why is my website still playing the original MP4?
Check the sources and their order in the published page. Remove an MP4 src on the video element itself if you intend the nested source list to select the file. If the MP4 is the first supported candidate, the browser may use it even when a smaller WebM exists. Confirm the requested URL in the network panel.
Does converting the video make a web page autoplay it?
No. Set up playback in the page or player. Browsers can restrict automatic playback with sound. For narration, provide a working play control and test the first visit before interacting with the page.
Can I convert MP4 to WebM with a transparent background?
This page has no background-removal or alpha-preservation control. A clip with a solid background does not become transparent by changing its container. For a transparent overlay, start with appropriate source artwork and verify alpha support throughout the export workflow.
How can I convert MP4 to WebM without any sound?
The converter normally carries a readable soundtrack. If the receiving app requires a file with no audio track, prepare a silent source using a tool that removes the track. Muting a player or lowering its volume does not remove the audio data.
Can I convert MP4 to WebM from a shared link?
Use a direct HTTPS link to the MP4 when its host permits the browser to read it. A page that displays a player or requires an account may not deliver the media file directly. Download the source first if necessary.
How do I convert MP4 to WebM for a site that also needs captions?
Convert the video and keep the caption file separately. Configure the web player to load the right captions, then test a sentence near the end. Text already drawn into the video stays visible as part of the picture.
Should I keep the MP4 after the conversion?
Keep it as an editing source or as a playback fallback. Name both files for the same revision of the demo. If the fallback shows an older interface, visitors may get different instructions depending on which video their browser chooses.