Unuploaded

Converter · No upload

Convert WAV to MP3 on your device

Convert WAV recordings to MP3 and compare the input and output sizes on each row.

Statusidle Files— File— Duration— PCM rate— Channels— Requested bitrate192 kbps Output size— Network since file read—

A file that will not decode gets a row saying it may be damaged or DRM-protected; any other extension is refused as not a WAV file. More than two channels are folded to stereo with a row note. Decode may resample a 96 kHz file without a note; the MP3-conform step notes further resampling. A float file's peaks above full scale are clipped without a note. Takes .wav and .wave.

How this converter works

Your browser reads the WAV into memory and decodes it with its own audio engine, so this page needs no extra audio decoder. The samples and your chosen bitrate go to lamejs, a JavaScript port of the LAME encoder (LGPL), which encodes the MP3 in this tab. Each result row gives a download link and the before and after sizes.

An hour of CD-quality audio is around 600 MB, and this tool reads all of it from your device. The network meter counts resource-timing entries from the first file read, so it does not include the encoder download that comes before it. To check that the tool works offline, convert one file while you are online so the encoder is cached, then disconnect from the internet and convert another. If it converts, the conversion did not need a server. The methodology page covers the other checks and the encoder’s license and provenance.

The bitrate choices are 128 kbps for smaller output, 192 kbps (the default) and 320 kbps. The bitrate readout and result rows repeat the request, not a measured MP3 bitrate, and at low PCM rates the encoder can use a lower bitrate. Browsers commonly decode at 44.1 or 48 kHz. The PCM rate readout shows the conformed sample-buffer rate sent to the encoder. That is not always the source WAV's rate, and it is not measured from the finished MP3. Samples are quantised to 16 bits, and cue points, broadcast-WAV notes and other non-audio chunks are not carried. There is no length cap: the whole recording is decoded in memory, and an hour of stereo at common browser rates needs over a gigabyte before other working buffers, so a long recording can run out of memory. A failed file gets a named error row, though the browser may not distinguish an unsupported codec, a damaged file and DRM protection.

Frequently asked questions
Is my recording uploaded anywhere?
No. The browser decodes the WAV, and the MP3 encoder in this tab writes the output. The page’s network meter is not a complete network audit; the methodology page describes other checks you can run yourself.
How much smaller will the MP3 be?
Roughly a seventh of the size at 192 kbps. A 16-bit, 44.1 kHz stereo WAV holds about 10 MB of audio per minute, and a 192 kbps MP3 about 1.4 MB; at 128 kbps the MP3 is roughly a tenth of the WAV. Other sample rates, channel counts and compressed WAV codecs give different ratios. The result row shows the input and output sizes for your file.
What bitrate should I choose?
Start with the default, 192 kbps. Try 128 kbps when a smaller speech file is fine, or 320 kbps, the highest setting, when file size matters less; at 320 kbps the audio takes about 2.4 MB per minute. If you are unsure, convert one file at two settings and listen.
Does converting WAV to MP3 lose quality?
Yes. MP3 encoding discards information, and a typical PCM WAV is uncompressed. WAV is a container, so some WAVs hold an already-lossy codec, and converting one of those adds another generation of loss. Keep the WAV or another lossless master, and use the MP3 as the copy you share.
What about unusual WAVs: 32-bit float, 96 kHz, multichannel?
The browser decodes the common studio variants, including 24-bit and 32-bit float, though not every WAV codec. A 96 kHz file may be resampled to the browser’s own rate before this page receives the samples. A multichannel file is mixed down to stereo, and the row says so. Broadcast-WAV cue points and embedded notes are not carried across.

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