Windows & Mac · Guide

How to Split a Large Archive Into Smaller Parts

Short answer

In 7-Zip's Add to archive dialog, use the "Split to volumes, bytes" field and enter a size such as 25M or 1900M. Send every resulting part; the recipient extracts by opening the .001 file.

Requirements

7-Zip on Windows or Keka on macOS
The files you need to send
The size limit imposed by your email or upload service

Steps

1. Find the real limit
Check the attachment or upload limit you are working against, then pick a volume size slightly below it to leave room for encoding overhead.
2. Open the archive dialog
On Windows, right-click and choose 7-Zip > Add to archive. On macOS, open Keka and set the split size on its main screen.
3. Enter the volume size
Use a suffix: 25M for 25 megabytes, 1900M for DVD-sized parts, 4000M to stay under FAT32's 4 GB file limit.
4. Create the archive
You will get files ending .001, .002, .003 and so on. All of them are required.
5. Tell the recipient how to extract
They must download every part into the same folder and open the .001 file. Opening a later part on its own will fail.

Alternative methods

1. Upload and share a link
For large transfers, a shared link avoids splitting entirely and is usually faster for both sides.
2. Use RAR recovery volumes
WinRAR can add recovery volumes so a damaged part can be rebuilt from the others, which matters for long-term storage.

Troubleshooting

Extraction fails with a missing volume error

One part did not download or was renamed. File names must keep their original numbering.

The parts are a different size than I set

The last volume is always smaller — it holds the remainder.

My cloud service rejects the parts

Some services scan archive contents. Reduce the volume size, or upload a single archive and share a link instead.

Frequently asked questions

Can I split an archive that already exists?

Not directly. Recreate it with a volume size set, or use PeaZip's convert function.

Do split archives compress worse?

No. Splitting happens after compression, so the total size is essentially unchanged.