Combining PDFs is one of those tasks that suddenly becomes urgent on the worst possible connection — at the airport, in a courthouse basement, on hotel Wi-Fi. Server-based mergers are useless there; this one isn't. Once the page is loaded, the merging engine (pdf-lib, a pure JavaScript PDF implementation) lives in your browser, and joining documents is local computation: page objects are copied from each source file into one combined document with no network in the loop.
Drop your files here or click to browse
.pdf — up to 200 MB each. Processed locally; never uploaded.
How to merge PDF Files — Works Offline
Open this page once while connected — that single load carries everything needed.
Drop your PDFs onto the box, in the order you want them combined.
Add more files in batches; remove any with the × button.
Click Merge — page trees are grafted together locally, connection or not.
Save merged.pdf straight to disk.
Frequently asked questions
Does merging really work with no connection?
Yes. Load the page, switch off your network, and merge — the PDF library is JavaScript already running in your tab, and files are read from and written to your own disk only.
Is there a privacy advantage beyond offline use?
A big one. Server mergers necessarily receive your documents — contracts, medical records, financial statements. Here the files never leave the machine, which also satisfies many workplace data-handling policies that prohibit third-party upload services.
In what order are the files merged?
Exactly the order shown in the file list — first file's pages first. Re-arrange by removing and re-adding files; each batch you drop is appended to the end.
Are there page or file-count limits?
No artificial ones. The ceiling is your device's memory, because the combined document is assembled in RAM. Everyday merges — dozens of files, hundreds of pages — are well within it.