Split PDF by Size
Split a PDF into multiple parts each under your target file size (MB).
Split by Size cuts a PDF into parts that stay under a size you choose — a portal's cap, an email limit — at the page boundaries that keep each part below the number; when a single page is itself larger than the limit, the tool says so for that part. Pages are not re-encoded.
Split by Size breaks a large PDF into smaller parts, each kept under a size limit you set in megabytes. It is useful when an email or upload form rejects files above a certain size. Split by Size is one of UnboundPDF's 53 free browser-based PDF and image tools: it runs on your own device with no upload, no account and no watermark, and reports what it measured on the output.
How to split by size — steps & common uses
What people use Split by Size for
Anyone hitting an upload or email size cap who needs a large PDF broken into parts that each stay under a limit.
- Fit parts under an email limit
- Meet a portal upload cap
- Break up a large scanned file
- Send a big report in pieces
How to split by size
- Add your PDF; it opens in your browser and stays on your device the whole time.
- Enter the maximum size in MB that you want each part to stay under.
- Click Split by size to pack pages into parts one at a time until each nears the limit.
- Download a ZIP containing the numbered parts.
Questions about Split by Size 6
Are my files uploaded to a server?
No. UnboundPDF processes PDFs locally in the browser — documents are not uploaded to a server. We have no backend that receives, stores, or scans your files.
What if a single page is larger than my limit?
Each part always contains at least one page, so a page bigger than the limit becomes its own part, and the tool tells you when that happens.
Are pages ever cut in half to hit the size?
No. Splitting happens only at page boundaries, so pages are never divided; parts are built by adding whole pages until the limit is reached.
How is the size limit applied?
You set a limit in megabytes, and each part is filled with as many whole pages as fit under it before the next part starts.
What if one page is larger than my limit?
That page becomes its own part — splitting cannot shrink a single page. Compress it first if you need it smaller.
Do the parts add up to the original?
Yes. Every page appears once across the parts, in order, with nothing dropped or duplicated.
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How your files are handled
The work runs on your own device, inside the browser tab — so there is no server to send your document to.
- Nothing is uploaded. We have no backend that receives or stores documents, so we cannot see your files during processing or after.
- Your device does the work. Large documents are handled in stages, pages are rendered as you reach them, and each job is checked against your device before it starts — so a long run takes longer on a phone than on a laptop, nothing is queued behind other people's jobs, and you can stop a run at any point without touching your original file.
- No account and no watermark. The output is a clean file you can use anywhere, with no sign-up and no hourly cap.
More organize tools
Other free PDF utilities that work the same way — in your browser, no sign-up.