How to Split a Large ZIP File Into Smaller Parts

You've got a 2GB archive and Gmail's attachment limit is 25MB. Or your client's file upload portal caps at 100MB. Or you need to transfer files via USB drives that are formatted FAT32, which has a 4GB-per-file ceiling. Or you're trying to email a large project to someone who's behind a corporate email gateway with a 10MB limit.

The solution is splitting the archive into smaller parts. But there are two very different ways to do this, and picking the wrong one causes real headaches on the receiving end.

Spanned Archives vs. Independent Parts

This is the most important distinction, and most people don't realize there are two approaches until they're staring at a set of files they can't open.

Spanned Archives (Traditional Split)

Traditional archive splitters — including WinRAR's "Split to volumes" and 7-Zip's split option — create spanned archives. A spanned archive is a single compressed stream chopped into sequential chunks. The files might be named archive.zip.001, archive.zip.002, etc. (or archive.z01, archive.z02 for the older convention).

To reassemble and extract a spanned archive, the recipient needs:

Every single part. If part 3 of 7 is missing or corrupted, nothing can be extracted. The parts are not independent — they're chunks of a single stream.
A tool that understands spanned archives. Windows' built-in ZIP extractor does not handle spanned archives. The recipient needs 7-Zip, WinRAR, or similar.
All parts in the same directory. The extraction tool reads them in sequence.

Spanned archives are space-efficient — the compression happens once across the entire set of files, then the compressed output is sliced. There's no duplicated overhead. But the dependency between parts makes them fragile and inconvenient.

Independent Parts (What MakeMyZip Does)

The alternative: split the files themselves across multiple independent ZIP archives. Part 1 contains files A through F. Part 2 contains files G through M. Part 3 contains files N through Z. Each part is a complete, standalone ZIP file that any standard ZIP tool can open.

Advantages:

Each part opens independently. The recipient can extract part 1 without having parts 2 and 3. If they only need one specific file, they can extract just the part that contains it.
No special software needed. Every operating system's built-in ZIP support opens each part. No WinRAR, no 7-Zip.
Parts can arrive out of order. If you're uploading to a portal that processes files one at a time, the order doesn't matter. Each part is self-contained.
A corrupted part doesn't destroy the others. If part 3 gets corrupted during transfer, parts 1 and 2 are still fully usable.

The tradeoff: total size across all parts may be slightly larger than a single spanned archive, because each part compresses its files independently rather than exploiting cross-file redundancy. In practice, the difference is usually under 5% and well worth the independence.

Common Reasons to Split Archives

Email Attachment Limits

This is the most common reason. Email providers enforce attachment size limits:

Gmail: 25MB per message
Outlook.com: 20MB per message
Yahoo: 25MB per message
Corporate Exchange: Often 10MB or lower, set by IT

If you need to email a 150MB archive, splitting it into six 25MB parts and sending them across six emails (or using a file-sharing link for the set) is often the simplest approach that doesn't require the recipient to install a file-sharing app or create an account somewhere.

Cloud Upload Limits

Some file-sharing services and client portals have per-file upload limits:

Many web-based portals cap at 50MB or 100MB per file
Some ticketing systems (Jira, ServiceNow) limit attachments to 10-25MB
Discord file sharing caps at 25MB (or 50MB with Nitro)

Splitting an archive to fit within these limits is faster than arguing with the portal's admin about raising the cap.

FAT32 Filesystem Limits

USB drives formatted as FAT32 (which is still the default for maximum cross-platform compatibility) have a hard 4GB-per-file limit. If you're transferring a 6GB archive via USB, you need to split it. This comes up surprisingly often when moving data between systems — especially when one system is a TV, game console, or embedded device that only reads FAT32.

Bandwidth and Resumability

If you're uploading to a server over an unreliable connection, smaller files are more resilient. A failed 25MB upload costs you 25MB of bandwidth to retry. A failed 2GB upload costs you 2GB. Splitting first means a transfer failure only affects one small part.

How the Splitting Algorithm Works

MakeMyZip's splitter uses a straightforward approach:

Extract the source archive. The input can be any supported format (ZIP, 7z, RAR, TAR, etc.). The tool extracts all files into browser memory.
Distribute files across parts. Starting with part 1, files are added sequentially until the next file would push the part over the size limit. Then a new part starts. Each file goes into exactly one part — files are never split across parts.
Compress each part independently. Each part is compressed as a standard ZIP file using DEFLATE compression.
Offer all parts for download. You can download parts individually or all at once.

There's an edge case worth understanding: if a single file is larger than the maximum part size, that file gets its own part. A 200MB video in an archive with a 100MB part limit will create a 200MB+ part containing just that one file. The tool warns you when this happens. There's no way around it without splitting individual files, which would make them unreadable.

Choosing the Right Part Size

The tool offers presets calibrated to common limits:

10MB: Conservative. Fits within virtually any email or upload limit. Use this when you don't know the recipient's constraints.
25MB: Matches Gmail and most webmail attachment limits.
50MB: Good for most cloud portals and file-sharing services.
100MB: Fits within most generous upload limits while keeping parts manageable.
250MB / 500MB / 1GB: For large archives where you're splitting for filesystem limits or bandwidth management rather than tight upload caps.

You can also enter a custom size in MB or GB. There's no minimum — the tool will dutifully create 1MB parts if you ask, though you'll end up with a lot of them.

Tips for the Receiving End

Since each part is an independent ZIP file, the recipient doesn't need special instructions. But a few tips make the process smoother:

Name the parts clearly. MakeMyZip names them filename-part1.zip, filename-part2.zip, etc. If you're emailing them, mention the total count: "Attached is part 1 of 4."
Include a manifest if the set is large. For 10+ parts, a quick text file listing what files are in which part helps the recipient find what they need without extracting everything.
Confirm receipt of all parts before deleting originals. If the recipient is missing a part, the remaining parts are still usable — but they won't have the complete set.

Reassembling Isn't Necessary

One of the key advantages of independent parts over spanned archives: there's nothing to reassemble. Each part is a regular ZIP file. The recipient extracts each one individually and ends up with all the files. If they want everything in one folder, they extract all parts to the same destination directory.

Contrast this with spanned archives, where the recipient needs to download all parts, place them in one folder, then use a specific tool to process them as a unit. Spanned archives are an artifact of the days when floppy disks held 1.44MB and you literally needed the archive to span physical media. That constraint hasn't applied in decades.

Step-by-Step: Splitting an Archive in Your Browser

Open MakeMyZip's archive splitter.
Drop your archive (ZIP, 7z, RAR, TAR, or GZ).
Choose a maximum part size from the presets or enter a custom value.
Click "Split Archive." The tool extracts the source, distributes files across parts, and compresses each part.
Download individual parts or all at once.

Everything runs in your browser. The source archive and all the generated parts exist only in your browser's memory. Close the tab and they're gone. No uploads, no server processing, no traces.

When Splitting Isn't the Right Approach

If you're splitting to work around email limits and the total size is over ~200MB, consider using a file-sharing service instead. Sending 8+ emails with 25MB attachments is technically possible but annoying for both you and the recipient. Dropbox, Google Drive, OneDrive, or WeTransfer will be a better experience at that scale.

If you're splitting for long-term archival storage (cold backups), consider whether spanned archives make more sense in your specific case. When you control both the creation and extraction and you're optimizing for total storage space, the cross-file compression of spanned archives saves meaningful space on multi-terabyte archives.

For everything else — fitting under an upload limit, working around FAT32, or making a large transfer more resilient — independent ZIP parts are the simpler, more compatible, and more robust choice.