Split Files

What is File Splitting?

File splitting is the process of dividing a large file into smaller parts based on a specified size or number of pieces. Due to email attachment limits, removable media capacities, and the need for easier upload/download, file splitting is a common operation. You can split large video files, backups, or archives into portable, manageable chunks.

PdfMetric's File Split tool splits your file into parts entirely in your browser. Files are not uploaded to any server; privacy is preserved. You can specify part size in MB or by number of parts. Split parts can later be reassembled with a merge tool. ZIP, 7z, or simple binary split formats are supported; parts are named with sequence numbers (e.g., file.part1, file.part2).

How Does File Splitting Work?

The split process reads the source file and writes it into parts of the specified size or count. For example, a 100 MB file split into 25 MB parts yields 4 parts. Part size can be set to match email limits (typically 25 MB) or USB/disk capacity. In binary split, file content is unchanged; parts are byte-for-byte segments of the original.

Some formats (e.g., ZIP split) make each part independently extractable; others require all parts to be present. Merging reassembles parts in order to recreate the original file.

When Should You Use It?

• Email transmission: Split files larger than the 25 MB attachment limit and send via multiple emails.
• USB/CD/DVD: Split large files into parts that fit 4 GB USB or 700 MB CD capacity.
• Cloud upload: On slow connections, split large files for incremental upload; if one part fails, retry only that part.
• Backup: Split backups to distribute across locations or stay within media size limits.
• Easier sharing: Smaller parts simplify download and management compared to one large file.

Technical Details

Split size is specified in bytes; 1 MB = 1,048,576 bytes. With streaming, large files can be split without loading them fully into memory. Part naming: file.part001, file.part002 or file.001, file.002. Merge order follows part number; missing parts cause merge to fail.

Advantages

• 100% privacy: Files are processed in the browser and never uploaded.
• Flexible size: Set part size or number of parts.
• Easy reassembly: Parts can be merged back with a merge tool.
• Email compatible: Split into parts that fit typical attachment limits.
• No installation: A web browser is sufficient.

Frequently Asked Questions

1. Select file: Upload the file to split.
2. Set part size: Specify size in MB or number of parts (e.g., 25 MB for email limit).
3. Start split: Click "Process".
4. Download parts: Download the resulting part files; keep them in the same folder.

Tip: For email, use 20-24 MB part size for a safety margin. When reassembling, verify order and completeness of all parts.