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Frequently Asked Questions
Where are my files processed?
Entirely in your browser. PDF Tools uses the open-source pdf-lib JavaScript library to manipulate documents on the client side — your files never reach our servers. You can verify this by opening your browser's Network tab while merging or splitting a PDF: there is no upload request. This means the tool also works offline once the page has loaded, and the speed is bound only by your local CPU.
How do I merge multiple PDFs?
Switch to the Merge tab, drop two or more PDF files into the upload area, drag them into the order you want, and click Merge. The result is a single PDF that preserves the original page order, fonts, and embedded images. There is no page limit beyond what your browser memory allows — typical laptops handle merges of several hundred pages without issue.
How does splitting work?
Switch to the Split tab, drop a PDF, and either pick page ranges (1-3, 7, 10-12) or extract every page as its own file. Each output PDF keeps the metadata of the source document. Useful for sending only the relevant portion of a long contract, separating chapters, or redacting by page.
Will the tool break encrypted or password-protected PDFs?
No — by design. Encrypted PDFs cannot be merged or split without the password. If you have the password, decrypt the file in a desktop reader (e.g. Adobe Acrobat or Preview on macOS) first, save an unprotected copy, then bring it here. We do not provide password-cracking functionality.
Are signatures preserved?
Visible signature graphics are preserved on the page. Cryptographic digital signatures, however, become invalid as soon as a PDF is modified — that is the whole point of a digital signature. If you merge or split a digitally signed PDF, the signature object will still be present but the signature will report as invalid. This applies to every PDF tool, not just ours; it is a property of the PDF specification.
What about file size limits?
There is no fixed limit imposed by the tool — the limit is your browser's memory. As a rule of thumb, a modern laptop will comfortably handle PDF files up to several hundred megabytes. Very large files (1 GB+) may be slow or crash the tab. If you hit that wall, consider splitting the source first into smaller chunks, processing them, then merging back.
Is there a desktop version?
Yes — we also distribute a free Electron-based desktop app for macOS, Windows, and Linux that uses the same engine. The desktop version handles larger files more gracefully and works without internet. See the project repository for download links.