Audio Converter
MP3 or OGG size = bitrate x seconds / 8: 3 minutes at 192 kbps is about 4.3 MB, while 3 minutes of 44.1 kHz stereo WAV is about 31.8 MB. Use 96 to 128 kbps for speech and 192 to 320 kbps for music. This converter changes WAV, M4A, FLAC, OGG and MP3 in your browser, with no upload.
How to use
- Drop an audio file onto the box or press it to choose one (WAV, M4A, FLAC, OGG, MP3, and the sound track of MP4, MOV or WebM videos). You can play it to check where to cut.
- Pick the output format and the bitrate. To keep only part of it, type the start and the end, in seconds or as m:ss. Leave the end empty to keep everything to the end. Tick Convert to mono for a single channel.
- Press Convert audio. The first time, the converter engine is downloaded once. When it is done, play the result and download it.
How it works
The audio is decoded and encoded with FFmpeg compiled to WebAssembly, inside this browser tab. MP3 uses the LAME encoder at a constant bitrate, OGG uses Vorbis, and WAV is uncompressed 16 bit PCM. The sample rate of the original is kept.
For MP3 and OGG the size is bitrate x seconds / 8: 3 minutes at 192 kbps is 192,000 x 180 / 8 = 4.32 MB, about 4.1 MiB. WAV is sample rate x 2 bytes x channels x seconds plus a 44 byte header: 3 minutes of 44.1 kHz stereo is about 31.8 MB. Mono halves the WAV size, and at the same bitrate it gives an MP3 more bits for the one channel.
Converting from a lossy format such as MP3 or M4A to another lossy format loses a little more quality each time, and a higher bitrate cannot bring back what was lost. Converting from WAV or FLAC keeps the best quality. 128 kbps MP3 is fine for speech, 192 to 320 kbps for music.
FAQ
Is my file uploaded?
No. The audio is read and converted inside this browser tab. The only download is the converter engine from this site. No upload, no account and no limit on how many files you convert.
Which bitrate should I choose for MP3?
For speech, podcasts and voice notes 96 to 128 kbps is enough, and mono saves even more. For music, 192 kbps sounds close to the original for most listeners and 320 kbps is the highest MP3 allows.
Can I convert FLAC to MP3 without losing quality?
MP3 is a lossy format, so some detail is always removed. At 256 to 320 kbps the difference is very hard to hear. If you need a lossless copy, convert to WAV instead, which keeps every sample.
Can I take the sound out of a video?
Yes. Choose an MP4, MOV or WebM video and the first audio track is converted. The picture is ignored, so the result is just the sound.
Does it work on a phone?
Yes, in a recent browser. On iPhone and iPad it needs Safari 16.4 or later. Audio files are small, so phones handle them well, but keep the tab open until it finishes.