Convert .dmg to .iso

I’ve wanted to make .iso images on my Mac for a while now. At last I’ve found this formula:

hdiutil convert /path/to/filename.dmg \
  -format UDTO -o /path/to/savefile.iso

To make the .dmg file, just click the ‘new image’ toolbar button in Disk Utility. .dmg format is called ‘read only’ in the dialogue box.

Just in: It seems that the ‘CD/DVD Master’ format (.cdr) is actually the same as .iso. You just need to change the extension! (I’ve not yet tried this.)

(Originally from

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  1. Alex said,

    28 January, 2006 @ 09:08

    Dude, also try hdiutil convert- format UDTO -ov /path/to/image.dmg -o /path/to/image.iso , it’s seems to be working for me.

    Cheers for pointing me in the right direction anyway.

  2. Brett said,

    17 June, 2006 @ 17:36

    In Mac OS X Tiger, DIsk Utility can convert .DMG to CD/DVD Master (.cdr)

  3. Josh said,

    8 July, 2006 @ 18:58

    hey were do you put the so you can convert it??

    /path/to/image.dmg -o /path/to/image.iso

  4. TJ said,

    18 July, 2006 @ 03:50

    Wow! It’s amazing I was just looking for something o accomplish just this task for Mac. My concern lays with the solution of creating a IS on MAc; so I’m attempting the .cdr and changing the extension. If it works, all hail your info!

  5. TJ said,

    18 July, 2006 @ 22:22

    Well the .cdr smply renamed didn’t work :(

  6. lubby said,

    5 August, 2006 @ 03:26

    used diskutil and saved as master CD/dvd. renamed the .cdr to .iso (using mv image.cdr image.iso). worked nicely.

  7. jason said,

    15 September, 2006 @ 09:42

    is it possible to convert .dmg to iso on a pc?

    if so, please tell.

  8. alsteig said,

    27 September, 2006 @ 21:36

    I want to change a .dmg to iso so I can transffer from my pc to a mac I tried dmgtoiso but the file is to big and they want me to buy the program. please help.

  9. Paige said,

    23 April, 2007 @ 16:43

    I’ve got a file that is .dmg . It won’t play on my computer. Is it compressed somehow? If so, how do I un-compress it?

  10. Charlie said,

    21 October, 2007 @ 13:40 i got leopard on a dmg. will it work if i convert to cd/dvd-r master using disk utility?

  11. michael said,

    26 October, 2007 @ 12:41

    i got mac os x tiger on (.cdr), i want to make this run on my pc, what do i do, please help!!!!

  12. Jay D said,

    20 February, 2009 @ 11:20

    renaming .cdr to .iso and then burning the iso does NOT make cd/dvd bootable ….

    damn i wasted my dvd ..

  13. poweriso said,

    29 January, 2011 @ 10:28

    I used PowerISO to wirte Snow Leopard from DMG in WIN7

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