Default Compression Settings

Default compression - What it is, how to change it

When you install WinZip a Default Compression Method is set. WinZip will use the default compression method each time you create a Zip file (.zip or .zipx). Exceptions to this, or methods you can use to create a Zip file and select a different compression method include, using Add to Zip file from the context menu, using WinZip Express, and creating a WinZip Job (WinZip Pro and WinZip Enterprise users only). The default compression method will also be used when you create Zip files from the context menu using Add to filename.zip.

The default compression method set during a WinZip install is Legacy compression , which will create .Zip files. You can change this to Optimize for best compression , which causes WinZip to create .Zipx files. Best method compression provides significant compression improvements over legacy Zip compression. Zipx files that you create will:

  • Be the smallest size possible with WinZip
  • Use advanced compression methods where applicable
  • Use the .zipx extension to clearly distinguish advanced compression Zip files from Legacy Zip files (.zip)

If you configure .Zipx in the Settings Tab to use one specific compression method, that will change the behavior and results described above.

Follow the instructions below to change the default compression setting in WinZip.

  1. Open WinZip
  2. Click the Settings tab and click WinZip Options
  3. In the WinZip Options General tab, click in the box next to Create new Zip files using the (.zipx) file type
  4. Click OK
  5. Close WinZip

If you will be sharing the Zip files that you create with others, and if they might not have a compatible WinZip version installed, you are welcome to have them download and install the latest evaluation version of WinZip. If installing a new build of WinZip is not acceptable to the recipient of your Zip files, you will likely want to configure the default compression setting to create .zip files.

!Choosing a Default Compression Method - Installing WinZip

With WinZip 21.5 or earlier, you can change the default compression setting while you are installing WinZip. To do this, you must choose the Custom install option in the appropriate panel and then make the change as pictured above.

If you have any questions about this information, please submit a Technical Support ticket.

Why don't some files compress very much?

!Some files don't compress much

Some types of files compress better than others. Certain data files, such as text files, picture files in the BMP format, and some text style database files can often be compressed by 90% or more. There are some other types of files, such as program files, that may compress by 50% or so. Learn how to make a zip file.

There also are other types of files that often will not compress well. For example, most multimedia files will not compress much, as they already exist in a highly compressed state. These file types usually employ efficient techniques to compress the data they contain. Examples include, but are not limited to, graphic (picture) files (GIF, JPG, PNG, etc), music files (MP3, WMA, etc), and movie files (AVI, MPG, etc). Files that are compressed, as these examples are, usually cannot be compressed more to any significant extent. Therefore, such files don't get much, if any, smaller when they are added to a Zip file (.zip or .zipx).

You would see a similar lack of compression if you zipped some files using maximum compression and then added that Zip file to another Zip file. This second Zip file would not be substantially smaller than the first one (it may even be slightly larger). Again, this is because the data in the original Zip file is already compressed. Some document files, including those created by Microsoft Office, are actually Zip files with a custom file extension.

There are other file types that don't compress well. For example, certain types of encrypted data files, such as those used by home finance programs and some spreadsheet products, will not compress very much.

If you are using WinZip 21 or later with MP3 files, you can use Best method and compress your MP3 files up to 20% more without loss of fidelity. If you are using WinZip 12 or later with JPG files, you can use Best method and compress your JPG files up to 20% more without loss of quality. With this setting, WinZip will use MP3 compression and/or Jpeg compression with files of those types and the result will be a Zipx file. If you are planning to share these Zip files with others, you should be sure that they are also using WinZip 21 or later to unzip MP3 files and WinZip 12 or later to unzip JPG files.

Again, if you create Zip files and see files that cannot be significantly compressed, it is probably because they already contain compressed data or they are encrypted.

If you would like to share a file or some files that do not compress well, you might:

If you have any questions about this information, please submit a Technical Support ticket.

Compiled from the official WinZip Knowledge Base (https://kb.winzip.com/)