Split PDF by Size — Parts Under 10 MB
Browser tool that splits a PDF on page boundaries into files below a chosen size
Runs in your browser · nothing is uploaded
Drop the PDF to split by size here
Add one PDF (up to 100 MB). Adding another file replaces the current one. Files never leave your browser.
What it does
It helps when an email or an upload form allows only, say, 10 MB per file. Starting from the first page, each part takes as many pages as fit under the size you set. Parts are named with a running number and their page range, so the recipient can keep them in order. Everything runs in your browser.
How to use
- Drop one PDF on the dashed area or press Choose PDF.
- Under Maximum size per file, pick 5, 10, 20 or 25 MB, or choose Custom and enter 0.1 to 2000 MB.
- Press Split by size. Progress is shown on the button by page.
- Check the page range and size of each part, then download them one by one or Download all (ZIP).
How it works
- Method: from the first page, runs of 1, 2, 4, 8… pages are saved for real until one exceeds the limit; the gap is then halved until the longest run that fits is found. The next part starts with the following page.
- Unit: 1 MB = 1,000,000 bytes, and the sizes in the list use the same unit, rounded down to two decimals.
- Oversized pages: a page larger than the limit on its own gets a file of its own and is flagged.
- What is copied: page content, size and rotation. Bookmarks and document properties are not included, and links to other pages may break.
- Limits: source files up to 100 MB and up to 300 parts. PDFs that need a password to open, or that carry editing restrictions, cannot be split.
- Libraries: pdf-lib (MIT) copies the pages and PDF.js (Apache-2.0) draws the preview.
Examples
| Situation | Setting | Example result |
|---|---|---|
| 35 MB scan for a 10 MB upload limit | 10 MB | part01-p1-12, part02-p13-25, part03-p26-38, part04-p39-45 |
| 20 MB mail attachment limit | 20 MB | Two parts |
| One page holds a 12 MB photo | 10 MB | That page alone, marked as over the limit |
Compressing the PDF first means fewer parts. To split by page ranges instead, use Split PDF.
FAQ
Is my PDF uploaded?
No. Splitting runs in your browser and the file is never uploaded. The parts stay on this device until you download them.
How many bytes is 1 MB here?
1,000,000 bytes. Some sites count 1 MB as 1,000,000 bytes and others as 1,048,576; fitting the smaller one passes either check. Your file manager may therefore show a 10 MB part as about 9.5 MB.
Can a page be cut in the middle?
No, parts always break between pages. If a single page is already larger than the limit on its own, it becomes a file by itself and is marked "single page over the limit". Compress the PDF first in that case.
Can I know the number of parts in advance?
Fonts and images that several pages share must be stored again in every part, so the real size is known only after saving. The tool therefore measures actual saved sizes as it adds pages, and lists the page range and size of each part at the end.
It takes a while. Why?
For each part the page count is doubled while the saved size fits, then the range is halved until the largest fitting run is found. Large files with many pages take longer. The page being processed is shown on the button, and **Stop** ends the run.
