A .zip file is a digital archive format that bundles one or more files or folders into a single, compressed container. It uses lossless compression algorithms, meaning the original files are perfectly reconstructed when unzipped, unlike formats like .jpg which lose some data. This reduces the file size for storage or transfer compared to sending individual files separately. Creating and opening .zip files is supported by most computer operating systems natively.

Common examples include downloading software installers or collections of documents from websites, where distributing multiple files as a single .zip saves bandwidth. Users also frequently zip large folders before attaching them to emails or uploading them to cloud storage platforms like Dropbox or Google Drive to meet file size limits and speed up transfers.

The main advantages are significant space savings and simplified file management for sharing collections. However, very large archives can be cumbersome to manage, password protection can be weak, and .zip files can sometimes be used to conceal malware. While newer, more efficient formats exist, the universal compatibility of .zip ensures it remains widely used for straightforward compression tasks.