Lossless baseline for further work.
ALAC preserves every detail of the source AAC, which prevents additional quality loss during subsequent edits or re-encoding. The original AAC compression cannot be undone, but no new artifacts will be introduced.
WHY CONVERT
01
ALAC preserves every detail of the source AAC, which prevents additional quality loss during subsequent edits or re-encoding. The original AAC compression cannot be undone, but no new artifacts will be introduced.
02
ALAC is accepted by a wider range of audio players, car stereos, and streaming services than AAC. The conversion removes a recurring compatibility friction without changing what the file actually contains.
03
ALAC files are typically smaller than their AAC counterparts, which reduces hosting, transfer, and storage costs at scale. The savings compound when serving the same content to many recipients.
Visit this page on any modern browser — no install, no signup, no plugin.
Drag your AAC into the drop area, or click to pick one from your device.
Conversion runs entirely in your browser. When it's done, your ALAC file downloads to your device.
QUALITY & FIDELITY
FORMAT SPECS
| AAC | ALAC | |
|---|---|---|
| Extensions | .aac | .m4a .caf |
| MIME types | audio/aac | audio/alac |
| Introduced | 1997 | 2004 |
| Maintainer | ISO/IEC (MPEG) | Apple |
| Magic # | FF F1 | — |
| Spec | View spec ↗ | View spec ↗ |
COMPATIBILITY
| Platform | Windows | macOS | iOS | Android | Chrome | Firefox | Safari | Edge |
|---|---|---|---|---|---|---|---|---|
| AAC | Native | Native | Native | Native | Native | Native | Native | Native |
Why LocalConvert
| Category | LocalConvert | Cloud converters |
|---|---|---|
| PRIVACY | Files never leave your device. The whole pipeline runs in your browser via WebAssembly. | Files travel to a remote server, sit in queue storage, and may be retained for analytics or moderation. |
| COST | Free, no signup, no daily quotas. | Often free for small files; paid tiers for batch / large / commercial use. |
| LIMITS | Limited only by your device's memory and CPU. Uncompressed WAV stems handled comfortably on desktop. | Typical 100 MB to 1 GB per-file caps, plus rate limits. |
The successor to MP3 with superior quality per bit. Used widely in streaming and modern audio.
Typical uses
YouTube, Apple Music, streaming services.
Apple's lossless audio format inside an M4A container.
Typical uses
Apple Music lossless, iTunes lossless libraries.
Yes. LocalConvert is completely free, with no signup and no per-file or per-day limits.
No. AAC to ALAC conversion happens entirely inside your browser using WebAssembly — your file never leaves your device.
There's no fixed cap — the practical limit is your device's available memory. Very large files may take longer or fail on low-RAM devices.
Yes — once the page has loaded, AAC to ALAC conversion works without an internet connection. Re-open the page once to cache it.
LocalConvert uses the industry-standard tools (FFmpeg, ImageMagick, Pandoc) — quality matches what professionals use on the command line. Lossy formats will still lose some quality on each re-encode.
Last verified:
AAC to ALAC is processed in your browser with WebAssembly. No upload, no tracking, no limits. Your file never leaves your device.