Convert WAV to M4A (AAC) Online
Convert uncompressed WAV to Apple M4A (AAC). Free, in your browser, no file uploads.
.wav · up to 100 MB
What you can do
WAV to M4A: the optimal PCM→AAC chain for the Apple ecosystem
Maximum AAC quality
Starting from uncompressed WAV guarantees the best possible AAC for a given bitrate, with no accumulated losses from previous encoding generations.
100% private
Your audio never leaves your device. No servers, no daily limits.
Full Apple ecosystem
M4A is the native format for iTunes, Apple Music, iPhone, iPad, GarageBand, and Logic Pro.
Podcasts and distribution
M4A/AAC is the standard delivery format for Apple Podcasts, Spotify, and music distribution platforms.
How it works
Three steps, no hassle
Upload your WAV file
Drag or select your .wav file. No signup, no limits. Files up to 500 MB.
AAC encoding in the browser
The uncompressed PCM from the WAV is encoded to AAC-LC (192–256 kbps) inside the M4A MPEG-4 container, without leaving your device.
Download your M4A
Ready to import into iTunes, Apple Music, iPhone, GarageBand, Logic Pro, or any podcasting platform.
FAQ
Got questions?
WAV stores audio as PCM (Pulse-Code Modulation) with no compression or transformation: each audio sample is saved as an exact integer value, with no prior encoding artifacts. When encoding from WAV to AAC, the encoder works on the original undegraded signal, producing the highest-quality AAC possible for a given bitrate. In contrast, starting from a prior MP3 or AAC (lossy compression) causes the encoder to accumulate quantization errors from two compression stages, a process known as 'generational loss'. For podcasts, music distribution, or Apple Music master files, WAV→M4A is the ideal workflow: uncompressed masters converted directly to the final distribution format.
AAC (Advanced Audio Coding, ISO/IEC 13818-7, published in 1997) is the audio compression codec. M4A is an MPEG-4 Part 14 container (a QuickTime extension) that contains AAC audio. The relationship is analogous to MP3 (codec) vs. an MP3 file with ID3 metadata (.mp3 file). M4A is the specific extension Apple uses to distinguish audio-only MPEG-4 files from MP4 video files, although technically both are MPEG-4 Part 14. iTunes, Apple Music, GarageBand, and Logic Pro recognize M4A natively and fully, including extended ID3 metadata, album artwork, and chapter markers (used in audiobooks and chaptered podcasts).
The 'transparent' quality of AAC (where most listeners detect no difference from the original in double-blind ABX tests) sits between 128 kbps (mono AAC-LC) and 192–256 kbps (stereo AAC-LC). This contrasts with MP3, which requires 192–320 kbps to reach transparency in stereo. Apple uses 256 kbps AAC-LC as its standard bitrate for Apple Music downloads (the 'iTunes Plus' AAC format since 2007), which is considered indistinguishable from CD quality (1411 kbps stereo PCM at 44.1 kHz) for the vast majority of listeners on home audio equipment.
M4A/AAC is broadly compatible beyond the Apple ecosystem. Android has supported AAC decoding since version 1.0 (2008). Major podcast hosts (Spotify, Apple Podcasts, Buzzsprout, Anchor/Spotify for Podcasters, Podbean) accept M4A as an upload format. Music streaming platforms like Spotify, Deezer, and Tidal also encode internally in AAC/OGG/FLAC and accept M4A as a master delivery format. The only major platform with limited M4A support is WhatsApp, which internally converts to Opus in an OGG container when receiving audio files.
WAV supports metadata through RIFF's INFO chunk (IART, INAM, IPRD fields for artist, title, album) and through ID3v2 embedded in an 'id3 ' or 'ID3 ' chunk. However, WAV metadata support in players and platforms is inconsistent. M4A uses the MPEG-4 'iTunes tagging' metadata system ('moov/udta/meta/ilst' boxes), which is the most fully supported audio metadata system in the Apple ecosystem and in cross-platform players. During WAV→M4A conversion, WAV ID3 tags are mapped to the equivalent M4A tags when available.
For Apple Podcasts, the RSS feed can reference M4A files directly; Apple Podcasts accepts them and transcodes for different devices as needed. For music distributors delivering to Apple Music (DistroKid, TuneCore, CD Baby), the M4A format (256 kbps AAC-LC, 44.1 kHz, stereo) meets Apple Music's technical delivery specifications. For high-resolution albums (24-bit/96kHz), Apple Music uses ALAC (Apple Lossless Audio Codec, also in M4A container with .m4a or .alac extension) rather than AAC. If the source WAV is 24-bit/96kHz, consider whether the final destination requires ALAC instead of AAC-LC.
Convert WAV to M4A: the optimal uncompressed-to-Apple-AAC chain
WAV (Waveform Audio File Format) is the standard audio format for uncompressed audio, developed by Microsoft and IBM in 1991 as a RIFF container for PCM (Pulse-Code Modulation) data. A stereo CD-quality WAV file contains PCM samples at 44,100 Hz, 16 bits per sample, with an uncompressed bitrate of 1,411 kbps, meaning one minute of audio takes approximately 10.5 MB. The absence of any compression stage makes WAV the absolute reference format for audio production: all professional DAWs (Pro Tools, Logic Pro, Ableton Live, Cubase, Reaper) use WAV as their internal working format and master export format. M4A is the MPEG-4 Part 14 container (an extension of Apple's QuickTime format, which in turn derives from MPEG-4 Part 12, a simplification of the QuickTime base) with AAC (Advanced Audio Coding) audio. AAC was jointly developed by AT&T Bell Labs, Fraunhofer IIS, Dolby Laboratories, and Sony in the MPEG-2 NBC (Non-Backwards-Compatible) project in the late 1990s, formalized as ISO/IEC 13818-7 in 1997 and then as MPEG-4 Audio (ISO/IEC 14496-3) in 1999. Apple adopted AAC in iTunes 1.1 in January 2003 as its preferred compressed audio format, displacing MP3, and since 2007 has offered its entire Apple Music catalog in 256 kbps AAC-LC without DRM (the 'iTunes Plus' format). The WAV→M4A conversion is the standard production chain for bringing uncompressed audio masters to Apple's digital distribution format.
The central technical advantage of using WAV as the source for encoding to AAC is the absence of generational loss. When re-encoding audio that has already gone through a lossy compression stage (for example, a 128 kbps MP3 converted to 192 kbps AAC), the AAC encoder works on a signal that already has quantization artifacts introduced by the prior MP3 encoder: the residual frequency modulation in MP3 scale bands, pre-echo distortion in transients, and ringing at the edges of high-frequency bands. When re-encoding, these artifacts are amplified or transformed into new AAC artifacts, producing an accumulation of audio degradation that can make the result sonically worse than either compressed format individually. An uncompressed WAV has none of these artifacts: the AAC encoder has access to the original PCM signal with 32-bit floating point or 16/24-bit integer precision, and can apply its psychoacoustic model (based on the auditory masking threshold and absolute threshold of hearing from ISO 226) without interference from prior artifacts, producing the highest-fidelity AAC possible for the selected bitrate. AAC-LC at 256 kbps encoded from 16-bit/44.1kHz WAV is considered by most listeners in controlled ABX tests to be transparent (indistinguishable from the original PCM), which is why it is Apple Music's distribution standard.
In 2025, WAV→M4A conversion is a central operation in several professional and semi-professional workflows. The largest in terms of users is podcast production: the standard workflow of a professional podcast producer starts with recording in WAV (condenser microphone through an audio interface at 24-bit/48kHz), editing and mastering in the DAW also in WAV, and final export to M4A (256 kbps AAC-LC, 44.1 kHz, mono or stereo) for uploading to platforms. Apple Podcasts, with over 500,000 active podcasts according to 2024 data, prefers M4A for its episodes for native compatibility with the Apple ecosystem. The second workflow is independent music distribution: artists and independent labels distributing through platforms like DistroKid, TuneCore, or CD Baby deliver their masters in 24-bit WAV for the platforms to encode to each service's distribution formats; for Apple Music, the result is AAC-LC 256 kbps in M4A. The third workflow is analog recording digitization: vinyl record and magnetic tape collectors who digitize their collections in high-resolution WAV (24-bit/96kHz in many cases) and want to create distribution copies for iPhone or AirPods without the massive size of FLAC or WAV files. A 5-minute 24-bit/96kHz WAV takes ~173 MB; the equivalent M4A at 256 kbps takes ~10 MB, a 94% reduction with transparent quality for home listening. Convertir.ai performs this conversion entirely in the browser, without uploading the file to any server.