Are my files uploaded to a server?

No. This conversion runs inside your browser using your own device’s processing power, and the file is not uploaded. Once a tool has been used once (video, text recognition and background removal download their engine from this site the first time), it keeps working when your connection drops.

How much quality is lost?

For speech, effectively none that you can hear. For music you are mixing or mastering, keep the WAV as the master and use MP3 only for sharing.

Is there a length limit?

No fixed limit — very long recordings are constrained by your device’s memory, so on a phone convert in sections if a multi-hour file stalls.

Convert WAV to MP3

Runs on your device · Your file never leaves your device.

WAV recordings from voice recorders and audio interfaces are large and awkward to share. Converting to MP3 makes the file much smaller; listen to the result before you share it.

This is the practical fix for a long meeting or interview recording that is too big to email or upload.

Conversion runs locally in your browser, so confidential recordings are never transmitted anywhere.

How to convert WAV to MP3

Add your WAV recording.
Press Convert — the audio is encoded to MP3 at the quality you choose (128 kbit/s unless you change it).
Download files a fraction of the original size.

Supported formats and limits

Input: WAV audio
Output: MP3
Typical saving: About 90% for CD-quality stereo at 128 kbit/s; less for a WAV that is already small, such as mono voice
Why convert: Email limits, phone storage, and players that expect MP3
Where it runs: In your browser; nothing uploaded

Not for: Master copies — MP3 is lossy, so keep the WAV if the file is a master you will edit again.

How much smaller the MP3 will be

An MP3’s size is set by the Quality setting and the length alone, so the saving depends on the WAV you start with. A WAV’s own rate is its sample rate × bit depth × channels. CD-format stereo (44.1 kHz, 16-bit) runs at 1,411 kbps, so the default 128 kbps MP3 is about 91% smaller. A 96 kHz, 24-bit studio file runs at about 4,600 kbps, and the same MP3 is about 97% smaller.

A mono WAV at 16 kHz, as some dictation and call recorders make, is only 256 kbps. At the default 128 kbps the MP3 is just half its size; 48 or 64 kbps brings it to a fifth or a quarter, which is the range meant for speech. A mono WAV stays mono in the MP3. Choosing a rate and the mono switch are explained on /mp4-to-mp3.

What a WAV carries that the MP3 will not

The WAV is decoded at its own sample rate. MP3 cannot store more than 48 kHz, so the encoder brings a 96 kHz recording down to 48 kHz; 44.1 kHz and lower rates are kept. A 24-bit or 32-bit depth is reduced to 16-bit before encoding.

Only the sound is carried. Markers, the recording date and time that field recorders write into a broadcast WAV, and any title stored in the file are left behind; the MP3 has no tags and takes the WAV’s file name.

A WAV with more than two channels is folded to stereo: in a 5.1 mix the centre and the surrounds go into both sides and the low-frequency channel is left out, while a multitrack recorder’s separate inputs are averaged together.

Unusual WAVs and very long recordings

Some recorders write WAV in a compressed encoding the browser cannot read. The site’s video engine, a download of about 30 MB, then reads it instead and hands it back as stereo, so switch on mono for a single-microphone recording.

The encoding runs in a background worker, so the page stays responsive during a long conversion. If the finished MP3 is still too large to send, the Split into parts tab cuts the recording into 2 to 50 equal MP3 files, delivered in one ZIP.

Frequently asked questions

Are my files uploaded to a server?: No. This conversion runs inside your browser using your own device’s processing power, and the file is not uploaded. Once a tool has been used once (video, text recognition and background removal download their engine from this site the first time), it keeps working when your connection drops.
How much quality is lost?: For speech, effectively none that you can hear. For music you are mixing or mastering, keep the WAV as the master and use MP3 only for sharing.
Is there a length limit?: No fixed limit — very long recordings are constrained by your device’s memory, so on a phone convert in sections if a multi-hour file stalls.