AAC vs FLAC: Which Should You Use?

Side-by-side comparison of AAC and FLAC audio formats — features, pros, cons, and conversion options.

Quick Answer

AAC is best for Streaming and mobile audio playback. FLAC is best for Archival audio storage and audiophile playback.

Quick Verdict

AAC Best for Streaming and mobile audio playback

✓ Excellent sound quality at low bitrates
✓ Wide device support
✓ Efficient compression
✗ Lossy compression

Convert AAC to FLAC →

FLAC Best for Archival audio storage and audiophile playback

✓ Lossless compression
✓ Open source
✓ Excellent metadata support
✗ Larger than lossy formats

Convert FLAC to AAC →

Specs Comparison

Side-by-side technical comparison of AAC and FLAC

Feature	AAC	FLAC
Category	Audio	Audio
Year Introduced	1997	2001
MIME Type	audio/aac	audio/flac
Extensions	.aac	.flac
Lossy	✓	✗
Codec	Advanced Audio Coding	FLAC
Max Bitrate	512 kbps	unlimited (lossless)
Max Sample Rate	96 kHz	655,350 Hz
Channels	7.1 surround	8 channels
Streaming	✓	✓

Pros & Cons

AAC

Pros

✓ Excellent sound quality at low bitrates
✓ Wide device support
✓ Efficient compression

Cons

✗ Lossy compression
✗ Not as universally supported as MP3
✗ Patent-encumbered

FLAC

Pros

✓ Lossless compression
✓ Open source
✓ Excellent metadata support

Cons

✗ Larger than lossy formats
✗ No native iOS support
✗ Not supported in all browsers

When to Use Each

Choose AAC when...

You need files optimized for Streaming and mobile audio playback
Excellent sound quality at low bitrates
Wide device support

Choose FLAC when...

You need files optimized for Archival audio storage and audiophile playback
Lossless compression
Open source

How to Convert

Convert between AAC and FLAC for free on ChangeThisFile

Convert AAC to FLAC Server-side conversion — auto-deleted after processing Convert FLAC to AAC Server-side conversion — auto-deleted after processing

Frequently Asked Questions

What's the difference between AAC and FLAC?

AAC is best for Streaming and mobile audio playback, while FLAC is best for Archival audio storage and audiophile playback. Both are audio formats but they differ in compression, compatibility, and intended use cases.

Is AAC or FLAC better for audio?

It depends on your use case. AAC is better for Streaming and mobile audio playback. FLAC is better for Archival audio storage and audiophile playback. Consider your specific requirements when choosing between them.

How do I convert AAC to FLAC?

Go to the AAC to FLAC converter on ChangeThisFile. Upload your file and the conversion processes on the server, then auto-deletes. It's free with no signup required.

Can I convert FLAC to AAC?

Yes. ChangeThisFile supports FLAC to AAC conversion. Upload your file for server-side conversion — files are auto-deleted after processing.

Which is smaller, AAC or FLAC?

File size depends on the content and compression settings. AAC uses lossy compression for smaller files. FLAC preserves full quality. For the smallest files, choose the format with lossy compression that meets your quality needs.

Does AAC support lossy?

Yes, AAC supports lossy, but FLAC does not. This may be important depending on your use case.

Is AAC or FLAC free to use?

Both AAC and FLAC are supported file formats that are free to use. You can convert between them for free on ChangeThisFile — server-side conversions are free with no signup required.

Which format is newer, AAC or FLAC?

FLAC is newer — it was introduced in 2001, while AAC dates back to 1997. Newer formats often offer better compression and features, but older formats tend to have wider compatibility.