Convert MP3 to AAC Online

This conversion re-encodes MP3 audio with the AAC codec, producing a raw .aac (ADTS) or MPEG-4-wrapped stream depending on the output settings. AAC is MP3's designed successor — standardised in MPEG-2/MPEG-4 — and is the required or preferred codec for HLS streaming, many broadcast pipelines, and video muxing workflows where an AAC track drops straight into an MP4 without re-encoding.

As a lossy-to-lossy transcode, quality can only go down slightly, so encode at or above the MP3's bitrate. AAC's efficiency advantage means an equal-bitrate AAC preserves the decoded signal at least as well as MP3 would, but it cannot restore anything the original MP3 encode discarded.

The most common real reason for this conversion is downstream tooling: preparing audio for HTTP Live Streaming, feeding an encoder that expects AAC input, or creating an audio track for video authoring. For simple playback, virtually everything that plays AAC also plays MP3, so conversion for its own sake is rarely needed.

Converting MP3 to AAC is a common requirement wherever different players, apps, and devices need to exchange audio. Whether you are preparing tracks for a music player, a podcast host, a video project, or meeting an upload requirement, having the file in the right audio format is the starting point for every workflow.

MP3 files are tied to specific software, codecs, and hardware. When that audio needs to move into a context that requires AAC - A different player, a DAW, a streaming platform, or a phone that only accepts certain formats - A fast, reliable converter removes the barrier without installing software or knowing anything about bitrates and codecs.

mp3.now processes your file securely in the cloud and returns a clean AAC output at the bitrate and quality you choose. Files are processed privately and automatically deleted after 24 hours - Nothing is stored beyond what is needed to complete your conversion.