MP3 to AAC Converter

Converting MP3 to AAC re-encodes the audio through a newer, more efficient lossy codec. AAC was specifically designed to replace MP3 and typically delivers comparable quality at about 70% of the file size, which is why every streaming service that matters has switched to it.

audio_file

Drag & drop audio files here, or browse

Drop your MP3 files here

What changes when you convert MP3 to AAC

You're transcoding between two lossy codecs, so a small quality drop is unavoidable. AAC at 160 kbps will generally sound as good as MP3 at 192 kbps, so you can drop bitrate slightly without making things worse. Target at least the MP3's bitrate to preserve quality.

When to use this conversion

  • Preparing audio for iTunes, Apple Music, or any Apple device that writes AAC by default
  • Optimizing for YouTube, which re-encodes all audio to AAC anyway (providing AAC saves one lossy round-trip)
  • Shrinking a music library for a phone or portable player without losing perceived quality
  • Feeding audio into video workflows (MP4, MOV) where AAC is the standard audio track format

Where the output plays

AAC is supported natively on iOS, macOS, Windows, Android (2.3+), and every mainstream browser. It's the default audio in MP4 video, so any platform that plays MP4 plays AAC.

About these formats

MP3 (MPEG-1 Audio Layer III)

MP3 is the most widely supported lossy audio format. Encoded in 1993 and still the default on countless devices, it trades some fidelity for dramatically smaller files. At 192 kbps most listeners cannot distinguish it from the source. Anything that plays audio will play MP3.

AAC (Advanced Audio Coding)

AAC is the successor the MPEG group designed to replace MP3. At 128 kbps it typically sounds as good as MP3 at 192 kbps. It's the default codec for YouTube audio, iTunes purchases, Apple Music, and nearly every streaming service that isn't using Opus or Vorbis.

How It Works

  1. Add your MP3 files Drag MP3 files onto the page, or click to pick them from your file browser. Batch uploads are fine.
  2. Choose AAC settings Pick bitrate or quality level for the AAC output. Defaults match common target use cases.
  3. Convert in your browser FFmpeg runs locally via WebAssembly. Nothing uploads. Progress shows per file so you know exactly what's happening.
  4. Download AAC files Grab each converted file individually, or download the whole batch as a single ZIP.

Features

Supported Formats

FAQ

Is AAC better than MP3?

At equivalent bitrates, yes. AAC produces noticeably fewer artifacts, especially at lower bitrates. The codec was designed as MP3's successor and achieves comparable quality at roughly 70% of the file size.

Should I use .aac or .m4a?

M4A, in almost every case. It's the same AAC audio but in a container that supports proper tags, album art, and chapters. Raw .aac is really only useful for streaming.

What is MP3 (MPEG-1 Audio Layer III)?

MP3 is the most widely supported lossy audio format. Encoded in 1993 and still the default on countless devices, it trades some fidelity for dramatically smaller files. At 192 kbps most listeners cannot distinguish it from the source. Anything that plays audio will play MP3.

What is AAC (Advanced Audio Coding)?

AAC is the successor the MPEG group designed to replace MP3. At 128 kbps it typically sounds as good as MP3 at 192 kbps. It's the default codec for YouTube audio, iTunes purchases, Apple Music, and nearly every streaming service that isn't using Opus or Vorbis.

Are my files private?

Yes. The converter runs entirely in your browser using FFmpeg compiled to WebAssembly. Your audio files are never uploaded, never sent to a server, and never leave your device.

Is there a file size limit?

There's no hard limit, but because everything runs in your browser you're bounded by available memory. Files over about 2 GB total can get slow or hit browser memory limits. Process in smaller batches if you run into issues.