Convert a DMG to ISO with hdiutil convert
Change a disk image between formats — DMG to ISO/CDR and back — in one command.
Run hdiutil convert with -format UDTO to produce a .cdr file, then rename it to .iso for cross-platform use.
01Command
Command
$ hdiutil convert ~/Desktop/image.dmg -format UDTO -o ~/Desktop/image.cdr && mv ~/Desktop/image.cdr ~/Desktop/image.iso02What it does
UDTO produces a hybrid CD/DVD-master image that Windows and Linux tools accept once renamed to .iso; use -format UDZO when converting back the other way. The original file is left untouched — convert writes a new one.
03Risk
!Warning: This only converts the container format; it does not decrypt an encrypted image without the password.
04Undo
✓No undo needed — this command does not change persistent state.
05Sources
- hdiutil – Create and manipulate disk imagesEvidence: hdiutil convert supports formats including UDTO (DVD/CD master) and UDZO; the output gets a .cdr extension that can be renamed to .iso.
Last verified: 2026-09-18 · Category: Files & Folders
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