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Split by Size
Split by Size divides a PDF into parts that each stay under a file-size limit you set. The tool estimates the average page weight and packs pages into parts until the target size is reached, which is exactly what you need for portals with hard upload limits.
How to use Split by Size
- Upload the oversized PDF.
- Enter the maximum size per part in megabytes, for example 5 MB.
- Run the split and download the parts; check each one against your upload limit.
Where Split by Size is useful
- Getting a large report under a government portal's per-file upload cap.
- Splitting a scanned archive into email-friendly attachments.
- Preparing parts for a system that rejects files over 10 MB.
Formats, algorithms and limits
The splitter calculates the average page size from the total file size and page count, then assigns a number of pages per part that should stay inside the limit. Because pages vary in weight, the estimate is based on averages, so an individual part can land slightly above or below the target.
Troubleshooting and honest limits
- Set the limit 5-10% below the real cap to absorb page-weight variation.
- For scanned documents with variable page sizes, verify each output rather than assuming equal sizes.
- If a single page is bigger than the limit on its own, no split can help — compress it first.
Frequently asked questions
Are the parts guaranteed to be under the limit?
The split uses average page size, so parts are targeted to the limit rather than absolutely bounded. Leave a little headroom and check the downloaded sizes, especially for scans with uneven pages.
Why is one part bigger than the others?
Pages differ in weight: a photo-heavy page can be ten times the size of a text page. The splitter packs pages evenly rather than bytes.
Can I set the limit in kilobytes?
Enter the value in megabytes; for a 500 KB limit use 0.5.
Does splitting degrade quality?
No. Pages are moved into new documents with their original streams, so image quality and compression are unchanged.
Related tools
Page written and reviewed by the FreeConvertio engineering team on 2026-10-14. Split by Size runs entirely in your browser — no uploads, no account and no daily limits.