Unuploaded

Converter · No upload

WAV to MP3, without uploading anything

Drop in WAV recordings and download MP3s a fraction of the size. The conversion runs entirely inside your browser — nothing is uploaded, which matters twice for WAV: recordings are private, and they're huge. The network meter below proves the zero live.

Statusidle Files— File— Duration— Sample rate— Channels— Bitrate192 kbps Output size— Network since file read—

How this converter works

When you choose a file, the browser's File API hands this page the bytes in memory — no transfer happens, because the file is already on your machine. Your browser decodes the WAV itself; PCM audio is the simplest thing a browser's audio engine reads, so this site ships no decoder at all for your files. The raw samples are then re-encoded to MP3 at the bitrate you chose by lamejs, a JavaScript port of the LAME encoder (LGPL), running inside this tab, and the result is handed back as a download link with the before and after sizes printed on the row. A server never appears in the pipeline because this site doesn't have one.

The encoder is the one thing that downloads, once — before any file of yours is read, so the network meter's zero is honest. WAV is where the local architecture pays twice: an hour of CD-quality audio is around 600 MB, which is a long upload to someone else's server and a non-event to read from your own disk. And you can run the strongest check yourself — let the encoder land, switch your wifi off, and convert. It still works. The methodology page covers the other verifications and publishes the encoder's license and provenance.

The honest limits: WAV to MP3 is a lossless-to-lossy conversion, so this is the one direction where the loss is entirely yours to choose — the WAV had everything, and the bitrate dial decides how much the MP3 keeps. 128 kbps is compact and fine for speech, 192 kbps (the default) is near-transparent for most music, 320 kbps is the format's ceiling. Keep the WAV as your master. Unusual rates and channel counts are remixed to what MP3 can hold — high sample rates come down to 44.1 kHz, surround mixes fold to stereo — and broadcast-WAV metadata is not carried across. A damaged file gets its own error row naming the problem rather than being silently skipped.

Frequently asked questions

Is my recording uploaded anywhere?
No. Your browser opens the WAV with its File API, decodes it itself, and a JavaScript MP3 encoder running inside this tab re-encodes it — all in memory, on your device. The readout's network meter counts every request from the moment your file is read and stays at zero, and the methodology page shows how to verify that independently. For hour-long recordings that would take minutes to upload elsewhere, skipping the upload is also simply faster.
How much smaller will the MP3 be?
A lot. CD-quality stereo WAV runs about 10 MB per minute; MP3 at the default 192 kbps runs about 1.4 MB per minute — roughly a seventh of the size. At 128 kbps it's about a tenth. The results row prints the before and after size for your actual file, which is the only number that matters for your recording.
What bitrate should I choose?
192 kbps, the default, is a sensible trade for music and mixed material. 128 kbps suits speech — interviews, lectures, voice notes — where the savings matter more than fidelity. 320 kbps keeps the most detail the MP3 format can hold, at about 2.4 MB per minute. If you're unsure, convert one file at two settings and listen: your ears on your material beat any rule of thumb.
Does converting WAV to MP3 lose quality?
Yes — that is the trade being made. WAV is uncompressed; MP3 keeps what hearing research says matters most and discards the rest, which is where the size savings come from. At 192 kbps and above most listeners can't tell on most material, but the loss is real and one-way: keep the WAV as your master, and treat the MP3 as the copy you share.
What about unusual WAVs — 32-bit float, 96 kHz, multichannel?
They convert. Your browser's decoder reads the common studio variants — 24-bit, 32-bit float, high sample rates — and anything MP3 can't hold is remixed by the browser's own resampler: high rates come down to 44.1 kHz and more than two channels are mixed to stereo. Broadcast-WAV metadata (cue points, embedded notes) is not carried across, since only the audio is re-encoded.

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