A ZIP file packs many files, or a whole folder tree, into one archive. It is the easiest way to send a set of documents as one email attachment, upload a project to a portal that accepts a single file, or keep a backup together. Text-based files such as CSV, code, logs and Word's older .doc files also get smaller.
This tool builds the ZIP inside your browser with fflate, a compression library that runs on your device. Add files with the file picker, choose a whole folder with "Choose a folder", or drag files and folders onto the page; folders keep their structure inside the archive. You can pick the compression level (none, fast, normal or maximum), name the archive, and leave out system files like .DS_Store and Thumbs.db. File names in any language are stored in UTF-8, so Hindi or accented names open correctly on Windows, macOS and Linux.
Limits: one ZIP can hold up to 5,000 files and 2 GB in total, because the archive is assembled in your browser's memory. Photos, videos, MP3s and PDFs are already compressed, so they barely shrink; by default they are stored as they are, which is much faster. Password-protected (encrypted) ZIPs and empty folders are not created.