DMG to 7Z Converter
Processing entirely on your device — large files may take a moment.
DMG is macOS's disk image: a UDIF container that can hold an HFS+/APFS filesystem, compression and even encryption. Every Mac app download ships as one. 7Z is ideal for big archives you store or share with power users; convert to ZIP when the recipient just needs to double-click.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How to convert DMG to 7Z
- 1
Select your files
Drag & drop your DMG files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to 7Z". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted 7Z file individually, or grab everything at once as a ZIP archive.
About the DMG format
DMG is Apple's Universal Disk Image Format: a UDIF wrapper that can carry an HFS+ or APFS filesystem, ADC/LZFSE/ZLIB compression blocks, and optional AES encryption. It is the distribution vehicle of every macOS application — double-click, drag, done.
The format is officially undocumented, which makes cross-platform extraction historically painful; 7-Zip's decoder handles the common compressed variants, letting any OS pull the payload out and repackage it as a plain ZIP or TAR.
+ Strengths
- ✓Native macOS distribution standard
- ✓Supports compression and encryption
- ✓7-Zip reads the common variants in-browser
! Limitations
- −Unofficial format — exotic variants may fail
- −Encrypted DMGs need a password
- −APFS volumes are partial-support
About the 7Z format
7Z is the native format of Igor Pavlov's 7-Zip (1999), built around LZMA/LZMA2 compression — for years the ratio king against ZIP and RAR — with AES-256 encryption, solid archiving (similar files compress as one stream) and open, unpatented specifications. A 7Z of the same photos or code is routinely 20–40% smaller than its ZIP.
The trade-off is platform defaults: Windows Explorer and macOS Archive Utility do not open 7Z without third-party tools (7-Zip, PeaZip, Keka). It is the format for maximizing compression on your own terms, and for encrypted archives done properly (header encryption included).
+ Strengths
- ✓Top-tier compression ratio (LZMA2)
- ✓Real AES-256 encryption, optional header encryption
- ✓Open format, free tooling everywhere
! Limitations
- −No native OS support — recipients need tools
- −Solid mode makes single-file extraction costly
Why convert DMG to 7Z?
There is a concrete reason this conversion exists: Unofficial format — exotic variants may fail 7Z sidesteps that — Top-tier compression ratio (LZMA2) If that is your situation, the tool above settles it in seconds, entirely on your device.
Frequently asked questions
Is this DMG to 7Z converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for DMG to 7Z?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Are the files inside my DMG archive modified?
No. Contents are unpacked in memory and repacked into 7Z byte-for-byte — the conversion changes the container, never the files inside it.
What about folders and directory structure?
The full directory tree is preserved: folders stay folders, and deep paths arrive exactly as they were packed in the DMG file.