Convert WAV to MP3
Turn a large WAV recording into an MP3 that plays on every phone, car stereo and music app, at about a tenth of the size. The file is never stored.
- Never stored
- No queue, no waiting
- No signup, no watermark
How it works
Add your WAV
Drop the file in. Its length, sample rate and channels are read straight away, so you can see what you are starting from.
Choose the bitrate
192 kbps suits music, 128 kbps is plenty for speech, 320 kbps keeps the most. The estimated size updates as you choose.
Download the MP3
One file, named after the WAV, ready to send or play anywhere.
What the encoder does with your samples
MP3 is not a sample format, which is why the WAV's bit depth stops mattering at the door. The encoder transforms the sound into frequency coefficients in blocks of 1152 samples and stores those, so a 24-bit master and a 16-bit copy of the same recording produce MP3s of the same size and very nearly the same sound. What does carry across untouched is the sample rate and the channel count.
The rate has a hard limit that belongs to the format rather than to this tool. MP3 defines 32, 44.1 and 48 kHz, along with their halves and quarters, and nothing else. A CD-rate or video-rate WAV is therefore encoded directly with no resampling, while a 96 or 192 kHz studio master is outside what an MP3 can be and has to be resampled before it can become one at all.
An MP3 is always slightly longer than what went into it. The encoder needs a run-up, so it writes a frame of near-silence at the front and pads the final frame out to a full 1152 samples at the end. Players normally trim both, using a header the encoder writes to say how much to skip — and that header is not written here, so a recording that began exactly on the beat begins about 25 milliseconds late. For listening that is invisible. For a seamless loop, a gapless album, or sound that has to line up with picture, it is not.
When you want something else
If the file is going somewhere modern rather than into a car stereo, MP3 is rarely the best format left: Opus at 64 kbps beats MP3 at 128 for speech, and ffmpeg encodes it in one line. If the WAV is a master, keep it, or make a FLAC — exactly these samples, roughly half the size, nothing discarded. And if gapless playback matters, encode with ffmpeg or Audacity, both of which write the header that lets a player trim the encoder's padding away.
Frequently asked questions
Which bitrate should I choose?
192 kbps is the sensible default for music — close to transparent, about 1.4 MB a minute. For speech, lectures, interviews and podcasts, 128 kbps sounds the same and halves the size again. Choose 320 kbps when the file will be listened to critically or converted again later.
How much smaller will it be?
About a tenth. A 50 MB WAV becomes roughly 5 MB at 192 kbps, or 3.5 MB at 128 kbps. The page shows the estimate before you convert, because the answer depends on length rather than on the WAV's own size.
Will it sound worse?
A little, and less than most people expect. MP3 discards what is hardest to hear, so at 192 kbps and above the difference is very hard to notice on ordinary equipment. What matters more is not doing it twice: encode once from the WAV rather than converting an MP3 into another MP3.
Is my file stored anywhere?
No. Nothing is stored, and a large recording converts without trouble.
Can I convert a long recording?
Yes. The MP3 is written to the browser's own storage as it is encoded rather than held in memory, so a several-hour recording converts without trouble. The progress bar shows how far along it is and can be stopped at any point.
What about mono?
If the recording is a single voice, converting it to mono halves the size again at no cost to how it sounds. The option is on this page, and the tool tells you when it has folded stereo down.
Good to know: Every pass through a lossy encoder throws a little more away, and it never comes back. Converting between MP3, AAC, OGG and Opus is one such pass. If you are going to edit the sound, convert to WAV first, do the work, and encode once at the end. MP3 carries at most two channels, so a surround WAV is folded down to stereo.
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