Convert almost any audio file to MP3 or WAV. Choose the bitrate, bit depth, sample rate and channels, convert a whole batch at once and download a ZIP. Your files are processed on your device and never uploaded.
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How to use the Audio Converter
Add your audio files: drop them on the box or click to choose. You can mix formats in one batch.
Pick the output format: MP3 for small files that play everywhere, WAV for lossless audio for editing.
Set the quality: choose the MP3 bitrate or WAV bit depth, and optionally a sample rate and mono or stereo.
Press Convert. Each file shows its progress and new size when it is finished.
Download each file, or press Download all (ZIP) to save the whole batch.
Audio formats compared
Audio formats are either lossless (every sample is kept exactly) or lossy (inaudible detail is discarded to save space). Uncompressed PCM size is easy to work out: bytes per second = sample rate × bit depth ÷ 8 × channels. CD audio is 44,100 × 16 ÷ 8 × 2 = 176,400 bytes per second, about 10.6 MB per minute. A lossy file at a constant bitrate uses bitrate ÷ 8 bytes per second: 192 kbps is 24,000 bytes per second, about 1.44 MB per minute.
Format
Type
Typical size per minute
Best for
WAV / AIFF (16-bit, 44.1 kHz stereo)
Uncompressed, lossless
10.6 MB
Editing, CDs, archiving
FLAC / ALAC
Compressed, lossless
about 5 to 7 MB (depends on the music)
Archiving music at full quality
MP3 320 kbps
Lossy
2.4 MB
High quality music that plays everywhere
MP3 192 kbps
Lossy
1.44 MB
Everyday music listening
MP3 128 kbps
Lossy
0.96 MB
Podcasts, audiobooks, sharing
AAC / M4A 256 kbps
Lossy
1.9 MB
Apple devices, streaming
Opus 96 kbps
Lossy
0.72 MB
Voice chat, web streaming
Recommended settings
Music for your phone or car: MP3, 192 or 256 kbps, keep the original sample rate, stereo.
Podcast or voice memo: MP3, 96 or 128 kbps, mono. Mono puts all the bits into one channel, so speech sounds cleaner at the same size.
Import into an editor or DAW: WAV, 24-bit, original sample rate, so later edits do not add rounding noise.
Video project: WAV at 48 kHz, the standard rate for video.
Speech recognition or telephone systems: WAV, 16-bit, 16 kHz (or 8 kHz for telephony), mono.
Avoid converting a lossy file to another lossy format more than necessary. Each lossy encode throws away a little more detail, so an OGG or M4A converted to MP3 sounds best at a high bitrate such as 256 or 320 kbps.
How the converter works
Your browser's built-in decoder (the Web Audio API) turns the file into raw samples at its native sample rate. The tool then mixes the channels if you asked for mono or stereo, resamples with the browser's high-quality resampler if you chose a new rate, and encodes the result: WAV is written directly as PCM, MP3 with LAME, the open-source encoder used by most desktop software. Nothing is sent to a server, so even long recordings convert quickly and stay private.
Frequently asked questions
Which audio formats can I convert?
Any format your browser can decode: MP3, WAV, M4A and AAC, OGG Vorbis, Opus, FLAC, AIFF and WEBM audio work in current Chrome, Edge, Firefox and Safari. Apple Lossless (ALAC) usually only decodes in Safari. Files can be converted to MP3 or WAV.
Are my files uploaded?
No. Decoding and encoding happen in your browser with the Web Audio API and a JavaScript build of the LAME MP3 encoder. Your audio never leaves your device.
MP3 or WAV: which should I choose?
Choose MP3 for listening, sharing and saving space: 192 kbps is about 1.4 MB per minute. Choose WAV when you want lossless audio for editing, burning a CD or importing into software that needs PCM; 16-bit 44.1 kHz stereo WAV is about 10.6 MB per minute.
Does converting improve quality?
No. Converting can keep quality or lose some, never add it. Converting a 128 kbps MP3 to WAV or to 320 kbps MP3 gives a bigger file that sounds the same as the 128 kbps original. Convert from the best source you have.
What sample rate should I use?
Keep the original unless you need a specific rate. 44.1 kHz is the music and CD standard, 48 kHz is used for video, and 16 kHz is enough for speech recognition. MP3 supports 8 to 48 kHz; higher rates such as 96 kHz are resampled to 48 or 44.1 kHz.
What does Normalize volume do?
It scales each file so its loudest peak reaches −1 dBFS, which makes quiet recordings louder without clipping. It changes peak level only; it is not loudness (LUFS) matching or compression.
Is there a file size or number limit?
There is no fixed limit. Large files need enough free memory because the whole file is decoded in the browser; files up to about an hour long work well on most computers.