WebM to MP4 Converter

Convert a .webm into an MP4 that plays on iPhones and everywhere else. Converted on your device — nothing is uploaded.

Drop your file here, or click to choose Processed privately in your browser — nothing is uploaded

Download
100% private. Your file is processed in your browser with ffmpeg (WebAssembly) and is never uploaded. Big or long files take longer and use more memory — for those, trim first.

How to Use the WebM to MP4 Converter

Three steps, all in your browser.

1

Load your WebM

Drag a .webm file onto the box or click to pick one. WebM is common from screen recorders and the web.

2

Convert to MP4

Click Convert. The VP8/VP9 video is re-encoded to H.264 and the audio to AAC in an MP4 container.

3

Download the MP4

Preview and download the .mp4 — ready for iPhone, video editors and sites that don’t accept WebM.

Frequently Asked Questions

How do I convert WebM to MP4?
Load your .webm file and click Convert. The tool re-encodes the VP8 or VP9 video to H.264 and the audio to AAC inside an MP4, all in your browser, then lets you preview and download the result.
Why convert WebM to MP4?
WebM is great on the web but isn’t supported by iPhones, many video editors, or some messaging apps and TVs. MP4 with H.264 is the most broadly compatible format, so converting lets the clip play and import almost everywhere.
Is my file uploaded to a server?
No. The conversion runs entirely on your device using ffmpeg compiled to WebAssembly. Your video is never uploaded, stored or logged, and the tool works offline once the page has loaded.
Will the quality drop?
Re-encoding is lossy, but the default CRF 23 setting keeps the MP4 visually close to the WebM for typical footage while keeping the size reasonable. For most uses the difference is not noticeable.
Can it handle WebM without audio?
Yes. Many screen-recorded WebM files have no audio track; the tool simply produces an MP4 with video only in that case. Files with audio keep their sound as AAC.

More video tools

MP4 to GIF

Turn an MP4 clip into a crisp animated GIF.

MOV to MP4

Convert QuickTime MOV to a playable MP4.

MKV to MP4

Convert Matroska MKV to a playable MP4.

AVI to MP4

Convert legacy AVI to a modern, smaller MP4.

GIF to MP4

Shrink an animated GIF into a small MP4.

GIF to Video

Convert an animated GIF into a video file (MP4).