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AC3 to MP3 converter

Convert AC3 to MP3 in your browser. No upload and no account: the file never leaves your device, so the only size limit is your device’s memory.

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Related conversions

Need it the other way round? Convert MP3 to AC3

Other ways to convert AC3

Convert other formats to MP3

Read more about the AC3 format and the MP3 format, or see every audio tool and all audio conversions.

Should you convert AC3 to MP3?

Fine when a player or app needs MP3. Converting between two lossy formats compresses the sound a second time, so match or exceed the original bitrate to keep the loss inaudible.

MP3 also plays in more places: every phone, computer, car stereo, speaker and app.

AC3 is Dolby Digital surround sound from DVDs and TV; MP3 is the most compatible lossy audio format ever made. Use MP3 when you don’t know what will play the file: cars, old players, podcasts hosts and upload forms all take it.

AC3 and MP3 compared
Property AC3 MP3
Compression Lossy Lossy
Typical quality 192–640 kbps, up to 5.1 128–320 kbps
Support Has patchy support Opens everywhere
Best for 5.1 surround soundtracks for DVDs and TVs Music and voice that has to play on anything
Introduced 1991 1993

How to convert AC3 to MP3

  1. 01

    Add your AC3

    Drop your AC3 file onto the box, or click to choose it. It is read from your disk and stays there.

  2. 02

    Check the settings

    The output is already set to MP3. Change the bitrate if you want to; the defaults suit most files.

  3. 03

    Save the MP3

    Press convert and save the MP3. Several files come back together as a ZIP.

What changes when AC3 becomes MP3

Two rounds of compression

Each lossy encode throws away a little more. A AC3 at 128 kbps converted to MP3 at 192 kbps sounds like the original; converted at 96 kbps it can turn swirly and dull.

Surround channels

AC3 is often 5.1 surround. Converting to MP3 mixes it down to stereo when MP3 can’t hold six channels, and dialogue may end up quieter than effects.

A one-time engine download

AC3 is decoded by FFmpeg compiled to WebAssembly, a 31 MB download the first time. After that it is cached, and the conversion never leaves your device.

Expect a smaller file

MP3 usually stores the same content in less space than AC3. AC3: About 3.4 MB a minute at 448 kbps. MP3: About 1 MB a minute at 128 kbps, 2.4 MB at 320 kbps.

This page is put together from our notes on each format, choosing only what is true of AC3 and MP3, so every pairing states the same facts the same way. How these pages are made.

Why it doesn’t upload

Recordings are often private: interviews, voice notes, unreleased music. Your browser can decode and encode audio itself, so there is no reason to send it anywhere.

How to check for yourself

Worth knowing

  • About the AC3. Converting a 5.1 AC3 to a stereo format mixes it down; dialogue that lived in the center channel can end up quieter.
  • About the MP3. Converting a low-bitrate MP3 to 320 kbps makes it bigger without making it sound any better; what was thrown away is gone.
  • MP3, WAV, M4A, OGG, Opus and FLAC are converted by your browser directly. WMA, AMR, APE, AC3 and the other specialist formats use the FFmpeg engine, a one-time 31 MB download.

Questions

Does converting AC3 to MP3 lose quality?

MP3 is lossy, so a little is discarded, but at the default bitrate the difference is inaudible for nearly everyone.

Will an MP3 play in my car or on my phone?

MP3 opens everywhere: every phone, computer, car stereo, speaker and app.

Read more about this

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