What Is a 7Z File?

How to Open, Edit, and Convert 7Z Files

Screenshot of several 7Z files in Windows 10 that open with PeaZip
7Z Files.

A file with the 7Z file extension is a 7-Zip Compressed file. A 7Z file is a bit like a folder on your computer, except that it really acts like a file.

Both a folder and a 7Z file can store one or more files, and even other folders. However, unlike folders, 7Z files are just single files with the .7Z extension that serve as a compressed archive of the data.

You'll most likely only see 7Z files when you download files from the internet that are bundled together, like computer software programs, picture albums, collections of documents... basically anything that might be downloaded best in a smaller, compressed form.

Some 7Z files are broken up into smaller chunks to make it easier to send or store them. They then end up with a different file extension, like .7Z.001.

How to Open a 7Z File

7Z files can be opened with a growing number of compression/decompression programs, but the free 7-Zip tool, created by the makers of the 7Z format, is probably your best on Windows, Linux, or macOS. With 7-Zip, you can extract (open) and even create your own 7Z files.

PeaZip is another favorite that supports extraction from, and compression to, the 7Z format.

On a Mac, Keka or The Unarchiver, both free, are two great alternatives for extracting 7Z files.

Sometimes, even after you've installed a file extractor program, just double-clicking won't open the 7Z file. A quick and simple workaround is to right-click the 7Z file and then choose to open it in the decompression program. In 7-Zip, this can be done via 7-Zip > Open archive, which will open the 7Z file in 7-Zip File Manager.

Screenshot showing how to use 7-Zip to open a 7Z file in Windows 8
Opening a 7Z File With 7-Zip (Windows 8).

Tip: If you want to preselect a program that will always open 7Z files when you double-click them, see our How to Change File Associations in Windows guide. Although this will let you change the program that automatically opens 7Z files, you can always use a different tool at any time by opening the other file extractor first and then loading the 7Z file.

There are also lots of free online 7Z file openers that don't require you to download any software at all, and that work on any operating system with a modern web browser. These work by letting you upload the 7Z to the website and then having you download any individual files out of the 7Z file.

B1 Online Archive and Archive Extractor Online are two free online 7Z file openers. Another is WOBZIP, which even supports opening password-protected 7Z files in your browser.

If you need to open 7Z files on a mobile device, free apps like iZip (iOS) and 7Zipper (Android) should work.

How to Open 7Z Part Files

Do you have multiple 7Z files that need to be opened together? If a 7Z file has been split into different parts, you must join them together in a very specific way in order to make the original file that you can then extract normally.

For example, maybe you have a part1.7z, part2.7z, part3.7z, etc. This can be confusing because if you open just one of those 7Z files, you'll likely find another file called something.001, and that pattern continues with each of the other 7Z files.

It's a bit confusing to grasp if you've never dealt with multipart 7Z files, so I suggest you read through these steps at Nexus Wiki for some picture instructions on how to combine the 7Z files to ultimately get to the content that's stored away in those parts.

Note: The instructions at Nexus Wiki are for opening something specific, and so the file names won't be the same as your files, but you can still use the steps to open anything similar that has multiple 7Z parts.

How to Convert a 7Z File

Remember that a 7Z file is really just like a folder that contains one or more files. This means you can't convert a 7Z file to PDF, DOCX, JPG, or any other format like that. A task like that would first require the files to be extracted out of the 7Z file and then individually converted with a different file converter.

Instead, the only other file formats that 7Z files can be converted to are other archive formats, like ZIP, RAR, ISO, and many others.

The easiest and quickest way to convert a small 7Z file is to use an online service. Zamzar is one in particular that can convert 7Z files to a number of other archive formats, like ZIP, TAR, LZH, and CAB.

Two other examples are CloudConvert and Convert Files, which are websites that can convert 7Z to RAR for free in your browser, as well as to other formats like TGZ. Like Zamzar, reserve these sites for smaller 7Z files since you have to upload the whole archive to the site before you can convert it, and then it needs downloaded in order to save it.

See these Free File Converters for Occasionally Used Formats for some other websites that can convert 7Z files.

If your 7Z file is large, or you want to convert 7Z to ISO, then it's probably best to use a dedicated, "offline" compression/decompression program, like IZArc, TUGZip, or Filzip.

More Information on 7Z Files

7Z is an open file format under the GNU Lesser General Public License.

The 7Z file format was originally released in 1999. It supports file sizes up to around 18 EiB (16 billion GB).

7Z does not store file system permissions. This means that you cannot set the permissions of files, store them in a 7Z file, and expect the same permissions to be retained when you extract the files.

The 7-Zip program lets you choose five different compression levels when making a new 7Z file, from Fastest to Ultra. You can even choose Store if you'd rather not compress the 7Z file, which will be quicker to create and extract files from later, but will also take up the most storage space.

If you do choose a compression level, you can pick from various compression methods, including LZMA2, LZMA, PPMd, and BZip2. Some other options when using 7-Zip to make a 7Z file include letting you pick a different dictionary size, word size, solid block size, number of CPU threads, and more.

Once a 7Z file has been created, you can add new files to it by simply dragging the files into the folder when it's open in 7-Zip (and probably other file compression programs, too).

If you're interested in reading the specifics on the 7Z file format, I recommend visiting 7-Zip.org.