Document Format Comparison

DMG vs ISO — Apple Disk Image vs CD/DVD Image

DMG (Apple Disk Image) is macOS's native disk image format — used for app distribution, backups, and disk images. ISO is the universal CD/DVD image format. DMG offers macOS-specific features like compression, encryption, and HFS+/APFS file systems; ISO is portable across every OS but limited to ISO 9660 or UDF.

DMGvsISO

Quick Verdict

Use DMG when…

Use DMG for macOS app distribution, encrypted disk images, and any Mac-only workflow. DMG's compression and encryption are tightly integrated with macOS.

Use ISO when…

Use ISO for cross-platform compatibility — distributing files that need to work on Windows, Linux, and macOS without conversion. ISO is the universal standard.

DMG vs ISO: Feature Comparison

Feature	DMG	ISO
Native platform	macOS	All operating systems
File systems supported	HFS+, APFS, FAT	ISO 9660, UDF
Compression	Yes (UDIF compressed)	No (raw)
Encryption	Yes (AES-128/256)	No (use external tools)
Burning to disc	macOS Disk Utility	Universal
Mounting on Windows	Requires HFSExplorer or similar	Native (Windows 10+)

When DMG wins

✓Native platform: macOS
✓File systems supported: HFS+, APFS, FAT
✓Compression: Yes (UDIF compressed)

When ISO wins

✓Native platform: All operating systems
✓File systems supported: ISO 9660, UDF
✓Compression: No (raw)

Frequently asked questions

How do I convert DMG to ISO?

On macOS: `hdiutil convert input.dmg -format UDTO -o output.iso && mv output.iso.cdr output.iso`. On Linux: `dmg2img input.dmg output.iso`. The conversion may fail for compressed or encrypted DMGs — decrypt first.

Can I open a DMG on Windows?

Not natively. Use 7-Zip (extracts files but not mounts as drive), HFSExplorer (mounts read-only), or commercial tools like TransMac. For sharing files across platforms, distribute as ZIP or ISO instead of DMG.