You need to email a folder of files, or get twenty documents under a single upload button. The classic answer is a ZIP archive — one file that holds many, usually smaller than the sum of its parts. You don't need WinRAR, 7-Zip or any install to make one; a modern browser can do it in seconds. Here's how, and when it actually helps.
What a ZIP actually does
A ZIP does two jobs at once: it bundles multiple files into a single container, and it compresses them using an algorithm called deflate. Deflate works by spotting repetition — repeated words, patterns and byte sequences — and storing each pattern once. The more repetitive the data, the more it shrinks.
What compresses well — and what doesn't
Shrinks a lot (50–80%): text documents, Word and Excel files, CSVs, code, log files, uncompressed bitmaps. These are full of the repetition deflate feeds on.
Barely shrinks: JPG photos, PNG images, MP3 audio, MP4 video and existing ZIPs. These are already compressed, so there's little repetition left to remove. Zipping them mainly bundles rather than shrinks — which is still useful when you need everything in one file. A good tool recognises this and stores such files as-is, so the archive never ends up bigger than the originals.
How to zip files in your browser
- Open the ZIP tool.
- Drag in your files, or click to select them (any file type works).
- Review the list and remove anything you didn't mean to include.
- Click Create ZIP — the archive builds and downloads as
archive.zip.
The result is a standard ZIP that opens by double-click on Windows, macOS and Linux — no special software on the receiving end.
Why local zipping matters
Most "zip online" websites upload your files to their servers, compress them there, and send the archive back. For public files that's merely slow; for contracts, tax documents, ID scans or anything private, it means handing sensitive data to a third party you have to trust. A browser-based tool assembles the ZIP entirely in your device's memory — your files never leave your computer, so there's nothing to intercept or store.
Common uses
- Attach a whole project to one email instead of ten separate files.
- Bundle scans and receipts into a single archive for records.
- Get multiple files past an upload field that only accepts one.
- Package images or documents to hand off to a client cleanly.
For sending lots of photos specifically, compress them first with an image compressor — since JPGs barely zip, shrinking them individually first is what actually reduces the total size.
Compress your images now
Ready to put this into practice? Use the free WebPcompress compressor — it runs entirely in your browser, handles 20 images at a time, and your photos never leave your device.