How to merge and split PDFs without uploading them
Put the PDFs of an assignment together into a single document, or break a long PDF into separate pages. It all happens in your browser, so your documents never leave your computer.
When it's useful
- Handing in your cover page, coursework and appendices as one file.
- Bundling the invoices, receipts or scans for a single application or expense claim.
- Pulling one page (a certificate, a table) out of a long PDF to email it.
- Splitting a course reader into chapters or pages.
Merge several PDFs into one
- On the home page, open the Standard Tools tab and choose PDF Engine. The direction should read Multiple PDFs → Merged PDF.
- Drag your files onto the dashed area, or click it to pick them. You can add them in several batches — they're added to the list.
- Check the list that appears below. Its order is the order of the final document: use ↑ and ↓ to move files and ✕ to remove one.
- Press Merge. A few seconds later
MERGED.pdfdownloads with every page, in that order.
Split a PDF into pages
- In PDF Engine, press the ⇄ button to switch to Source PDF → ZIP.
- Pick or drop a single PDF.
- Press Extract.
Split_PDF.zipdownloads, with one file per page (Page_1.pdf,Page_2.pdf…). - Unzip it (a double-click is enough on Windows and macOS) and keep the pages you need.
Why your files are safe
Most PDF-merging websites upload your documents to a server, process them there and send the result back. Zero7Files uses the open-source pdf-lib library, which runs inside your browser: it copies the pages of your PDFs into a new document in your computer's memory and hands it to you as a download. You can check it yourself: once the page has loaded, turn off your Wi-Fi and the tool keeps working.
Common problems
"Error processing the file"
This usually happens with password-protected or damaged PDFs. Open the PDF in your reader, save it again with "Print → Save as PDF" and try once more.
The final file is large
Merging doesn't compress: the result weighs roughly the sum of the originals. If they're scans, lowering their resolution before merging helps the most.
Very large files
Since your own computer does the work, PDFs of hundreds of megabytes may be slow or run out of memory on older phones. On a normal computer it's rarely a problem.