What Is a ZIP File?

This article describes what ZIP files are and why they're used in some situations. We'll also look at how to open one to see its contents, and how to convert the files inside to a different format, or convert the ZIP itself to another archive format like TAR.GZ or RAR.

What Is a ZIP File?

A file with the ZIP file extension is a ZIP compressed file and is the most widely used archive format you'll run into. Like other archive file formats, this one is simply a collection of one or more files and/or folders, but is compressed into a single file for easy transportation and compression.

ZIP File Uses

The most common use for ZIP files is for software downloads. Zipping a software program saves storage space on the server, decreases the time it takes for you to download it to your computer, and keeps the hundreds or thousands of files nicely organized in a single file.

Another example can be seen when downloading or sharing dozens of photos. Instead of sending each image individually over email or saving each image one by one from a website, the sender can put the files in a ZIP archive so that only one file needs to be transferred.

How to Open a ZIP File

The easiest way to open a ZIP file is to double-click it and let your computer show you the folders and files contained inside. In most operating systems, including Windows and macOS, ZIP files are handled internally, without the need for any extra software.

While that is the easiest way to open a ZIP file, these archives sometimes hold executable files that can't run properly unless they're unzipped first. Or, if there's a file inside the ZIP archive that you want to save to a different format, you need to extract that file out of the archive first.

To do this in Windows, open the ZIP file as I described above, and then use the Extract all or Extract button (it's different for different Windows versions) at the top of File Explorer to choose a folder on your computer to copy the files to. That folder is now a copy of the contents of the ZIP file, but all the files are more easily accessible for you to use (like to run a program or convert a file).

Other Tools and Capabilities

There are many compression/decompression tools that can be used to open (and create!) ZIP files if you don't want to go with the built-in function on your computer.

Including Windows, just about all programs that unzip ZIP files also have the ability to zip them; in other words, they can compress one or more files into the ZIP format. Some can also encrypt and password protect them.

If I had to recommend one or two, it'd be PeaZip and 7-Zip, both excellent and completely free programs that support the ZIP format.

Online and Mobile Options

If you'd rather not use a program to open the archive, lots of online services support the format, too. Services like Files2Zip.com, B1 Online Archiver, and ezyZip let you simply upload your ZIP file to see everything inside, and then you can download one or more of the files individually.

You can also open one on most mobile devices. iOS users can install iZip for free, and Android users should be able to work with ZIP files via B1 Archiver or 7Zipper.

Opening Other Kinds of ZIP Files

ZIPX files are Extended Zip files that are created by and opened with WinZip version 12.1 and newer, as well as PeaZip and some other similar archive software.

If you need help opening a .ZIP.CPGZ file, see What Is a CPGZ File?.

How to Convert a ZIP File

Files can only be converted to something of a similar format. For example, you can't convert a JPG image into an MP3 audio clip, any more than you can convert a ZIP file to PDF or MP4.

If this is confusing, remember that ZIP files are just containers that hold compressed versions of the actual file(s) you're after. So if there are files inside a ZIP file that you want to convert—like for a PDF to DOCX or MP3 to AC3—you must first extract the files using one of the methods described in the section above, and then convert those extracted files with a file converter.

With that said, converting between archive formats is fair game (see below), just like how you can convert between image formats. So, if you want to convert ZIP to 7Z or TAR.GZ, you just need to find a converter that supports those formats.

Recommended Converters

Since ZIP is an archive format, you can easily convert one to RAR, 7Z, ISO, TGZ, TAR, or any other compressed file, in two ways, depending on size:

• If it's small, I highly recommend using ConvertFiles or Online-Convert.com. These work just like the online ZIP openers described above, which means you'll need to upload the file to the website before it can be converted.
• To convert larger ZIP files that would take much longer to upload to a website, use Zip2ISO for conversion to ISO, or IZarc to convert it to lots of different archive formats.

If none of those methods work, try one of these Free File Converters for Occasionally Used Formats to convert the file to another file format. The one I particularly like is Zamzar, which can convert to 7Z, TAR.BZ2, YZ1, and a few other archive formats.

More Information on ZIP Files

Below are related details that come up when talking about this format.

Password Recovery for ZIP Files

If you've password protected the file but then forgot the password, you can use a password cracker to remove it to regain access to your files. One free program that uses brute force to remove a ZIP password is ZIP Password Cracker Pro.

ZIP Files Have ZIP Extensions

Some ZIP files may have a file name with a different file extension before the final "zip" extension. Just keep in mind, like with any type of file, it's always the very last extension that defines what the file is.

For example, Photos.jpg.zip is still a ZIP file because JPG comes before ZIP. In this example, the archive is probably named this way so it's quick and easy to identify that there are JPG images inside the archive.

Backups

Some backup software tools will create file backups in the ZIP format so that they're compressed to save space, collected together for easier retrieval, and contained in a common format so that the backup can be opened even without the original backup software. One such program that does this is COMODO Backup.

Creating a ZIP File

To make a ZIP file in Windows, right-click the files and/or folders that should be in the archive and then choose Send to > Compressed (zipped) folder. In Windows 11, you'll need to select Show more options to see that menu.

To zip up files/folders in macOS, right-click them and select Compress Items from the menu to make an Archive.zip file.

If you'd rather make the archive online, I recommend TinyWow's ZIP creator.

Size Limitation

A ZIP file can be as small as 22 bytes and as large as around 4 GB. This 4 GB limit applies to both the compressed and uncompressed size of any file inside the archive, as well as to the total size of the ZIP file.

ZIP's creator Phil Katz' PKWARE Inc. has introduced a new ZIP format called ZIP64 that raises the size limitation to 16 EiB (around 18 million TB). See the ZIP File Format Specification for more details.