How to use the MP3 to WAV Converter
Drop in your MP3 files
They are decoded by your browser and never transmitted.
Check the sample rate
It is read from the MP3 frame header and matched automatically, so the WAV comes out at the rate the MP3 was encoded at.
Download the WAV
Expect it to be about ten times the size of the MP3. That is the format, not a setting.
This does not improve the audio, and it is not meant to
"WAV" is not a synonym for "CD quality". A WAV file stores exactly the samples it is given, so decoding a 128 kbps MP3 to WAV produces a file roughly ten times the size containing precisely the audio that was in the MP3 - the same missing detail, the same artefacts, now stored uncompressed. Nothing is recovered, because there is nothing left to recover.
If you have been asked for "a WAV instead of that MP3" because the WAV will sound better, the request is based on a misunderstanding and converting will not satisfy it. What is needed is the original recording, not a re-wrapped copy of the MP3.
The legitimate reasons, which are all about the container
Plenty of software will only import PCM. Hardware samplers, older versions of audio editors, some game engines and audio middleware, a good deal of broadcast and telephony tooling, and most command-line audio processing expect a WAV and will refuse an MP3 outright. That is a real problem and this is the real fix.
There is also encoder delay. An MP3 carries a small amount of silence at the start and end that the codec added, and different decoders handle it differently - which matters if you are sample-aligning audio to a video or to other tracks in a session. Decoding once here, deliberately, and working from the PCM removes that variable from the rest of the process.
And there is simple robustness: a WAV has no codec to go wrong. If a file has to survive being opened by unknown software in ten years, uncompressed PCM with a 44-byte header in front of it is about as safe a bet as digital audio offers.
What the file size will be
Uncompressed stereo at 44.1 kHz and 16 bits is about 10.1 MB per minute, whatever the MP3 it came from was. A four-minute track is roughly 40 MB, an hour-long recording roughly 600 MB. The bitrate of the source changes none of that - a 128 kbps MP3 and a 320 kbps MP3 of the same length produce WAV files of the same size.
Converting to mono halves it, and dropping the sample rate to 22.05 kHz halves it again, both of which are reasonable for speech. Neither makes the audio better; they just make the file smaller for a purpose that does not need the rest.
Frequently asked questions
- Will converting MP3 to WAV improve the quality?
- No. The WAV stores exactly what the MP3 decoded to, including everything the MP3 encoder discarded. It will be about ten times larger and sound identical.
- Why would I want a WAV then?
- Because something you are using requires PCM - a sampler, an older editor, a game engine, a broadcast tool - or because you want to remove MP3 encoder delay from a session where you are aligning audio precisely.
- How large will the WAV be?
- About 10 MB per minute for stereo at 44.1 kHz, regardless of the source bitrate. Mono halves it; halving the sample rate halves it again.
- Is my audio uploaded anywhere?
- No. The MP3 is decoded by your browser and the WAV is written on your own device. Nothing is transmitted.
- What sample rate does the WAV use?
- The one your MP3 was encoded at, read from its frame header and set as the default before anything is decoded. You can override it, but it will not be changed without you.