WebM to MP4 Converter – Free Online

How to Convert WebM to MP4 Online

Drop your WebM file

Drag and drop your .webm file onto the box above, or click Choose Files. The request is already filled in: “Convert this to MP4”.

Say how, if you want

The AI assistant uses sensible defaults. To choose the resolution, frame rate or bitrate yourself, say so in the request, for example “Convert this to MP4 in 720p”.

Save your MP4 file

The assistant opens with your file and converts it on your own device; the file itself is never uploaded. When the MP4 file is ready, click Save. Prefer to set everything by hand, or batch-convert several files into a ZIP? The classic converter is one click away on this page.

Why Convert WebM to MP4?

WebM is great inside Chrome but Safari, iOS, PowerPoint, Premiere Pro and most TVs will not open it. Converting WebM to MP4 re-encodes the VP8 or VP9 video to H.264 and the Opus audio to AAC, giving you a file that plays and edits anywhere.

Screen recordings from Chrome extensions, Loom and Google Meet are the most common WebM sources. Drop the file in, keep the resolution, and the converter produces a standard MP4 on your own machine with no upload and no waiting in a queue.

Private by design: your WebM file is converted on your own device and never uploaded.
MP4 already asked for: the AI assistant's request says MP4, so one drop does it. Want a particular resolution, frame rate or bitrate? Just say so.
Batch friendly: the classic converter on this page takes several WebM files in one go and downloads them as a ZIP.
Free, no watermark: no sign-up, and nothing stamped on the output.

WebM vs MP4

WebM (WebM): WebM is the open, royalty-free container built for the web. It pairs VP8, VP9 or AV1 video with Opus or Vorbis audio and streams natively in Chrome, Firefox, Edge and HTML5 players. It is best for HTML5 video, websites and open-source projects.

MP4 (MPEG-4 Part 14): MP4 is the most widely supported video container in the world. It usually carries H.264 or H.265 video with AAC audio, plays on every phone, browser, TV and editing app, and is the safest choice for sharing. It is best for sharing, social media, web playback and mobile devices.

In short: keep WebM when the priority is HTML5 video, websites and open-source projects, and switch to MP4 when the file is headed for sharing, social media, web playback and mobile devices. Need a different target? The full Video Converter supports every format listed below.

WebM to MP4 FAQ

Why is WebM to MP4 slower than other conversions?

WebM video must be fully re-encoded from VP8/VP9 to H.264, which is CPU-intensive. Long recordings take a few minutes; the page shows live progress.

Can I convert a WebM file that has no duration?

Yes. Browser screen recorders often omit the duration header. The converter scans the whole file, so the MP4 gets a correct length and seek bar.

Is this WebM to MP4 converter free?

Yes. Converting WebM to MP4 on MediaConverter.io is free, with no watermark and no sign-up. The AI assistant runs on a free daily allowance of assistant credits; the classic converter on this page has no daily limit at all.

Are my WebM files uploaded to a server?

No. The conversion runs inside your browser using WebCodecs and FFmpeg compiled to WebAssembly, so your .webm file is read and converted on your own device and never uploaded, which keeps private recordings private and means there is no waiting in an upload queue. The AI assistant only sees what you type and basic facts about the file: its name, format, duration and size.

Is there a file size limit for WebM to MP4?

There is no plan or account limit, but the converter loads the whole WebM file into your browser's memory, so about 2 GB per file is the practical ceiling; larger files may fail to open. Long or high-resolution files also take longer, especially on phones.

Can I choose the MP4 settings myself?

Yes. Ask the AI assistant for a resolution, frame rate or bitrate in your request. Audio and subtitle track selection, the codec list and every other setting are in the classic converter, one click away on this page.

Will converting WebM to MP4 reduce quality?

The video is re-encoded into MP4. Keep the source codec, resolution and bitrate (the defaults) and an ordinary 8-bit video is visually the same as your WebM, while a 10-bit, HDR or full-color (4:2:2 or 4:4:4) source can lose some color detail. Lowering the bitrate or resolution is what reduces quality, and you control that trade-off by asking for it (or in the classic converter's settings).

Which browsers support the WebM to MP4 converter?

It is built and tested on current desktop Chrome and Edge, which are also fastest because they expose hardware-accelerated WebCodecs video decoders. Recent Firefox and Safari releases support the same web APIs; if a file fails there, try Chrome or Edge.