No, the entire conversion happens locally in your browser using the Web Audio API for decoding and the lamejs JavaScript library for MP3 encoding, your audio content is never transmitted to any server. This also means conversion works without an internet connection once the page has fully loaded.

WAV stores every audio sample uncompressed, which is why a typical 3 to 4 minute stereo song in WAV format takes up 30 to 40MB, while the same audio compressed to MP3 at 192 kbps takes up only about 4 to 5MB, roughly an 85 to 90% reduction. MP3 achieves this through psychoacoustic compression, discarding audio information that’s largely imperceptible to human hearing rather than simply storing fewer samples.

For music where quality matters, 320 kbps (the maximum standard MP3 bitrate) is essentially indistinguishable from the original for most listeners and equipment. 192 kbps is a well-regarded balance point used as the default by many services, offering very good quality at roughly 60% the file size of 320 kbps. 128 kbps noticeably reduces file size further but can introduce audible artifacts in complex audio, it’s most appropriate for voice recordings, podcasts, or situations where storage space matters more than audio fidelity.

Yes, since the tool relies on the browser’s built-in audio decoder (the same one used by the HTML5 audio element), it can generally decode any format your browser supports, including MP3, OGG, M4A/AAC, and FLAC, not just WAV. WAV to MP3 is the primary use case since WAV files benefit the most from compression, but re-encoding other formats to standardize on MP3 or reduce bitrate also works.

Encoding is a computationally intensive process performed entirely on your device’s processor rather than a powerful server, so a 5-minute song might take several seconds to encode depending on your device’s speed, and much longer audio files (an hour-long podcast, for example) can take a noticeable amount of time. This is the trade-off for keeping your audio completely private and never uploading it anywhere.

No, MP3 compression is lossy, meaning some audio information is permanently discarded during encoding and can never be recovered, even if you convert the MP3 back to WAV afterward, the file will be larger again but the lost detail is gone for good. If you need to preserve a pristine master copy, always keep your original WAV file and treat the MP3 as a compressed copy for playback or distribution.

There’s no hard limit built into the tool itself, since everything processes in your browser’s memory rather than through a server upload quota, but very long audio files (over an hour) may take a while to encode and could use a significant amount of memory, particularly on mobile devices with less available RAM.

This tool encodes up to 2 channels (mono or stereo); if your source file has more than 2 channels (like 5.1 surround), only the first two channels will be used in the resulting MP3, since standard MP3 encoding is built around mono and stereo audio rather than multi-channel surround formats.