How to use the WAV to MP3 Converter
Drop in your WAV files
They are read directly by your browser. Large files are fine up to 200 MB.
Check the sample rate
It is read from the WAV header and matched automatically, so a 48 kHz master stays at 48 kHz rather than being quietly resampled.
Pick a bitrate
192 kbps for general listening, 256 or 320 kbps for music you care about, 128 kbps mono for speech.
Download the MP3 and keep the WAV
The MP3 is a copy for distribution. The WAV is the master, and you cannot get it back from the MP3.
The conversion MP3 was built for
A WAV is uncompressed PCM - the raw samples, nothing thrown away. Encoding it to MP3 is a first-generation lossy encode from an intact source, which is the case every psychoacoustic model in the encoder was tuned for. At 192 kbps and above the result is very hard to distinguish from the original on normal playback equipment, and it is roughly a seventh of the size.
The arithmetic is stark. Stereo 44.1 kHz WAV is about 10 MB a minute, so a ten-minute recording is 100 MB. The same recording at 192 kbps MP3 is about 14 MB. That is the difference between a file you can email and one you cannot.
Keep the WAV
This is the one instruction worth repeating. The MP3 is a distribution copy. The moment you delete the WAV, the discarded detail is gone for good, and every future edit, re-encode or format change starts from the lossy file and compounds.
If the WAV is a recording you made - an interview, a rehearsal, a field recording, a podcast take - archive it somewhere before you convert. Storage is cheap; a re-record is not, and for most of these there is no re-record.
Sample rate, and why it is not just left at 44.1 kHz
Every browser-based converter decodes through the Web Audio API, and that API always resamples to whatever rate the audio context was created at. A converter that hardcodes 44.1 kHz therefore downsamples a 48 kHz master on every single file, silently, and reports nothing about it.
This page reads the declared sample rate straight out of the WAV header before decoding anything and sets the control to match, so the default is your file rather than a convention. Change it deliberately if you want to - 22.05 kHz is a reasonable choice for speech and halves the size again - but it will not happen behind your back.
Frequently asked questions
- How much smaller will the MP3 be?
- At 192 kbps, roughly a seventh the size: 100 MB of stereo WAV becomes about 14 MB. At 320 kbps it is about a quarter, and at 128 kbps about a tenth.
- What bitrate should I use?
- 192 kbps is the sensible default for a first-generation encode. Use 256 or 320 kbps for music you care about, and 128 kbps mono for speech, where it is both smaller and perfectly clear.
- Is my audio uploaded anywhere?
- No. The WAV is read by your browser and the MP3 is encoded by a worker on your own device. For a 100 MB file that also means no upload wait.
- Can I convert back to WAV later?
- You can produce a WAV from the MP3, but it will not be the original. The detail the encoder discarded is gone, and the WAV will simply store the compressed result at ten times the size. Keep the original WAV.
- Why is my file over 200 MB refused?
- Because decoding happens in your browser, and decoded audio is far larger than the file on disk. The limit is set where a tab would otherwise be at risk of running out of memory mid-conversion.