How to split a ZIP file
- Drop one ZIP onto the drop zone above, or click to choose it.
- Set the Maximum part size (MB). The default is 25.
- If the ZIP is encrypted, enter Password (only if the archive is encrypted).
- Click Split. The parts are named after the original, for example
photos.part1.zip,photos.part2.zipand so on. - Download each part with its own button, or use Download all (ZIP) to save them together.
Splitting runs entirely in your browser. The archive is not uploaded anywhere.
Independent parts, not split volumes
Desktop archivers such as WinZip and 7-Zip can create multi-volume archives: a set of files like backup.z01, backup.z02 and backup.zip that are really one archive cut at arbitrary byte positions. A file can be sliced across two volumes, and the recipient needs every piece, in the same folder, plus software that understands spanned archives. If a single volume is lost, files that crossed the gap cannot be recovered.
This tool takes a different approach. It sorts the files into groups and writes each group as a complete, normal ZIP:
| Multi-volume (.z01, .z02…) | Split ZIP here (.part1.zip…) | |
|---|---|---|
| Open one part on its own | No | Yes, with any ZIP tool |
| Files cut in half | Possible | Never |
| Part sizes | Exactly equal | Up to the limit, varying with file sizes |
| Missing part | Whole set may fail | Only that part's files are missing |
Because each part is self-contained, a recipient on a phone or using Windows File Explorer can open whichever part arrives first.
How files are distributed
Files are taken in archive order and added to the current part until the next one would push it past the limit; then a new part begins. The limit is measured against each file's compressed size inside the ZIP, so parts end up close to, but not exactly at, the size you chose. A single file larger than the limit cannot be divided, so it gets a part of its own that is bigger than the maximum.
Two situations stop the split with a message: an archive containing only one file, and an archive that already fits within one part. In the second case, choose a smaller part size.
For email, remember that attachments are encoded for transport, which makes them roughly a third larger. A 25 MB attachment limit is therefore better served by a part size of about 18 MB.
Tips
- Check what is inside first with ZIP Viewer; the Packed column shows whether one huge file will dominate a part.
- If one oversized PDF or photo set is the problem, shrink it with Compress PDF or Compress Image before splitting.
- The recipient can recombine everything into one archive with Merge ZIP.
- The parts are written without a password. Encrypt each one with Password Protect ZIP if the contents are sensitive.
Frequently asked questions
Why is one part bigger than the size I set?
It contains a single file that is larger than the limit on its own. Files are never cut in half, so that file gets its own part.
Do I need all parts to open the files?
No. Every part is a complete ZIP. You only need the parts that hold the files you want.
Can I make .z01/.z02 volumes instead?
No, this tool only creates independent ZIP parts. Use a desktop archiver if your recipient specifically needs a spanned archive.
Are folder paths kept in each part?
Yes. A file keeps its full path, so extracting all parts into the same location rebuilds the original folder structure.