Convert WebM to MP3
Pull the sound out of a WebM video or recording and save it as an MP3, without uploading it.
- Nothing is uploaded
- Works offline after first use
- Open source
- No sign-up, no watermark. The limit is your device’s memory (phones hold less).
Extract the audio from WebM videos and recordings as MP3 in your browser. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The limit is your device’s memory, which is smaller on a phone, and after your first run the page works offline.
Your iPhone may take a few seconds to prepare the video first, longer if it's stored in iCloud.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
WebM is what the web records in. Chrome and Firefox save screen and microphone captures as WebM, so do tools built on them: browser voice recorders, some meeting and interview recorders, OBS in some setups, and a lot of video downloaders. The audio inside is Opus or Vorbis. It plays fine in a browser, but podcast hosts, transcription services, iTunes and most audio editors want an MP3.
The whole conversion happens in this tab. Your browser demuxes the WebM, decodes its soundtrack and hands the samples to the LAME MP3 encoder built into the page; the video frames are simply ignored, so even a long screen recording converts quickly. No part of the recording goes to a server, which is the point when it is a meeting, a lecture or a call.
The page opens at 128 kbps, a good match for Opus audio from recordings. For a talk with one voice, choose 96 kbps and mono: an hour-long recording comes out around 40 MB.
How it works
- Drop one or more .webm files, or tap to pick them.
- Keep 128 kbps, or pick 96 kbps mono for a single speaker.
- Convert, and the MP3 downloads. Several files come as a zip.
In your browser, not on a server
Your browser decodes the sound track with the same audio decoders it uses to play media on any website (AAC for MP4, MOV and M4A; Opus or Vorbis for WebM; FLAC, WAV and MP3). The samples are resampled to 44.1 kHz and handed to LAME, the reference MP3 encoder, compiled to WebAssembly and served by this site. WAV files are written directly by a few lines of code in the page. Everything happens in memory in your tab.
Compared with upload-based tools: Online converters upload the whole video just to keep its sound, cap free files at a few hundred megabytes, and make you wait in a queue. Home videos, lectures and voice memos are personal. Here the file never leaves your device, so a 1 GB video converts as fast as your computer can read it, and the limit is your device’s memory (phones hold less).
Verify it yourself. Give the page a short while after your first run to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
Does it work with WebM files that have no video?
Yes. Audio-only WebM, which many browser voice recorders save, converts the same way.
My screen recording has no sound in the MP3. Why?
Most likely the recording itself had no audio track: browsers only record sound when you tick "share audio" or allow the microphone. If the WebM plays silently in a video player too, there is nothing to extract.
Can I get a WAV for editing instead?
Yes. Switch the output format to WAV. It is uncompressed, so about 10 MB per minute of stereo, but it is what audio editors prefer.
Where do WebM files usually come from?
Browser screen and tab recorders, Chrome and Firefox microphone recorders, OBS set to WebM, and many video download tools all save WebM, because browsers can write it without licensing fees. Most carry Opus or Vorbis sound, which this page decodes in any current browser.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after your first run to save itself for offline use; then you can turn off Wi-Fi and it still works.
More video and audio tools
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Pull the sound out of a video, or turn any audio file into an MP3. Your files are converted on this device and never uploaded.
Video to GIF
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GIF to MP4
Turn animated GIFs into small MP4 videos that post and play anywhere. Converted on this device, never uploaded.
Compress video
Make a video a fraction of the size, or fit it under a limit like 10 MB for Discord or 25 MB for email. It is compressed on this device and never uploaded.
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Guides
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- Is Convertio safe?Convertio is a well-known converter with a published deletion policy. For private files, the safer choice is a converter that never receives them.
- Is Zamzar safe?Zamzar is one of the oldest online converters. Its storage window is longer than most, which is the detail worth knowing.
- A free CloudConvert alternative for everyday filesCloudConvert measures its free tier in credits tied to conversion time, not files, which makes it hard to predict when you will hit the limit. Here is an alternative with nothing to meter.
- A free Convertio alternative with no file size capConvertio's free plan caps both file size and how many conversions you get per day. Here is an alternative with no such ceiling.