Here is one such small tool dmg2iso which converts (z-lib compressed).dmg images to iso images on windows. However if you want to open.dmg file on windows than its not possible with help of any tool. To convert DMG file to ISO format, please follow the steps, 1.
On a Windows PC, AnyBurn can convert DMG file to ISO format, or burn it to a blank CD / DVD disc. Usually, the data in DMG file is stored in compressed format. The DMG file can be burned to a CD or mount as a normal volume on Macintosh computers. To do that, complete the following steps: Pick USB option on sidebar, or in the main window, then choose Create a Bootable USB.
You can use Windows To Go on any PC just after you plug in your Hard Drive. Create the independent workspace on your USB drive with DAEMON Tools Lite 10.8.