Does WebM to MP4 reduce quality?

The video is re-encoded to H.264. On the High setting the difference is not visible.

Will the audio be kept?

Yes. Opus or Vorbis audio is converted to AAC inside the MP4.

Is there a file size limit?

Browsers handle roughly 1 GB in memory. Files under about 300 MB and 1080p are comfortable.

Yes. No sign-up, no watermark, and the file stays on your device.

Free · No sign-up

WebM to MP4

Convert a WebM screen recording or download into an MP4 that plays everywhere – no upload, no sign-up, no watermark added.

AI · Paid creditsAI Video Watermark Remover AI Video Eraser

No upload
No sign-up
No new watermark
MP4, MOV, WebM, MKV, AVI

Drop a video here or click to choose

MP4, MOV, WebM, MKV, AVI · best under 300 MB

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A real input to try

Start with an openly licensed sample.

Belong Waterfall video MRD by Mike Dickison, from Wikimedia Commons under CC BY 4.0. This unchanged WebM contains audible natural waterfall sound for editing, conversion or audio extraction.

Still preview of the original video input — Input · video/webm

This card shows an input, not a processed result. Loading it does not upload it or start a paid task.

Source: Mike Dickison · CC-BY-4.0
Input: 608 × 1080 · 1.57 MiB

Attribution and modifications · Media facts and hashes

WebM is the format browsers produce. Screen recorders built into Chrome, Loom-style tools and many download sites save VP8 or VP9 video in a WebM container. It plays fine in a browser, but iPhones, video editors and most social apps want MP4.

This converter re-encodes WebM to MP4 with H.264 video and AAC audio. Drop the file in and click Convert. The result opens in iMovie, Premiere, CapCut, PowerPoint and any phone gallery.

The conversion runs in your browser with FFmpeg WebAssembly. Your recording is never sent to a server, and nothing is added to the output.

Screen recordings with no duration

Browser-made WebM files often lack a length header, so players cannot seek. Converting to MP4 fixes this and adds a proper duration.

Transparent WebM

MP4 cannot store transparency. If your WebM has an alpha channel, the background becomes black in the MP4.

Long recordings

An hour-long screen recording can be several hundred megabytes. Cut it into sections with the video cutter first to stay under the browser's memory limit.

All tools

A place for every edit.

Remove a logo, refine your footage, change a format or take the sound with you. Find the tool for your next step.

15 tools

Watermark removal

Start with the part you want to remove.

10 tools

Edit video

Shape the frame, timing and movement.

7 tools

Convert

Get the format your next step needs.

3 tools

Audio

Keep the sound, without the video.