Is it free to convert between AU and AMR?

Yes, Convert999 is 100% free. All conversions happen locally in your browser with no file size limits, no registration, and no watermarks.

.au

.amr

AU vs AMR

Compare Sun Audio and Adaptive Multi-Rate Audio formats — understand the key differences and when to use each

Format Overview

AU

Sun Audio

Sun Audio (.au) is a audio file format.

.auaudio

AMR

Adaptive Multi-Rate Audio

Adaptive Multi-Rate Audio (.amr) is a audio file format.

.amraudio

AU vs AMR: Feature Comparison

Feature	AU	AMR
Full Name	Sun Audio	Adaptive Multi-Rate Audio
File Extension	.au	.amr
Category	audio	audio
Free to Convert	✓ Yes	✓ Yes
Browser Support	✓ All Browsers	✓ All Browsers
Convert to Each Other	✓ Yes	✓ Yes

When to Use AU vs AMR

Use AU when you need:

•Files in Sun Audio format for maximum compatibility
•Industry-standard audio format support
•Wide software and platform compatibility

Use AMR when you need:

•Files in Adaptive Multi-Rate Audio format for specific workflows
•Optimized audio format features
•Modern format advantages and smaller file sizes

Convert Between Them

AU AMR AMR AU

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Frequently Asked Questions

What is the difference between AU and AMR?

AU (Sun Audio) and AMR (Adaptive Multi-Rate Audio) are both audio file formats. AU files use the .au extension while AMR uses .amr. They differ in compression, quality, compatibility, and intended use cases.

Can I convert AU to AMR for free?

Yes! Convert999 lets you convert AU to AMR completely free, directly in your browser. No file upload to any server, no registration needed — your files stay private on your device.

Which is better, AU or AMR?

It depends on your use case. AU (Sun Audio) may be better for certain workflows, while AMR (Adaptive Multi-Rate Audio) excels in others. Consider factors like file size, quality, software compatibility, and your specific needs.

Is it safe to convert files on Convert999?

Absolutely. Convert999 processes all files 100% locally in your browser. Your files are never uploaded to any server, ensuring complete privacy and security.

AU Converter

Convert from AU

AMR Converter

Convert from AMR

File Tools

Compress, resize, merge

Convert to AU

All sources → AU

Convert to AMR

All sources → AMR

Format Statistics

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Feature

AMR

Full Name