Combining PDFs is the most common thing anyone needs to do to one, and it is usually the moment a document gets uploaded to a stranger's server. A signed contract, a set of invoices, a bank statement, scanned ID pages for a KYC submission. All of it routinely goes through a free web tool that keeps a copy.

This one does not. Your files are read into memory by the browser, combined there, and handed back as a download. No upload step exists in the code, so there is nothing to opt out of and nothing to delete afterwards.

Order is the part people get wrong

Most merge tools combine files in whatever order the operating system handed them over, which is usually alphabetical and almost never what you wanted. Files named scan1, scan2 and scan10 sort as 1, 10, 2. Add your files here, then move each one up or down until the list reads the way the finished document should, because the merge follows that list exactly.

What carries across and what does not

Pages, their content and their size and rotation all carry through unchanged. Form fields, annotations and bookmarks are not guaranteed to survive a merge in any tool, this one included, because the combined document has to resolve conflicts between identically named fields. If the source files contain filled forms, flatten them before merging and check the output.

Working with large files

Everything runs in the tab, so the ceiling is your device's memory rather than an upload limit. A few hundred pages is comfortable on an ordinary laptop. Very large scanned documents, the kind where every page is a full-resolution photograph, are heavier and worth merging in smaller batches.

Encrypted files

A PDF that opens without asking for a password will merge. One that is password-protected on open cannot be read without that password, and this tool does not attempt to bypass protection. Remove the password in your PDF reader first, then merge.

Frequently asked questions