Merge PDF

Combine multiple PDF files into one. Drag to reorder pages before merging. Free and private.

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Drop PDF files here or click to select

Multiple files allowed — drag rows to reorder

About this tool

Merging multiple PDF files into a single document is one of the most common PDF tasks — combining scanned pages, assembling a multi-chapter document, or consolidating reports. Most desktop PDF tools that do this require an expensive subscription. This tool merges PDFs entirely in your browser using the pdf-lib library, so your documents never leave your device. Drag to reorder files before merging.

  • ✅ Free to use, no sign-up required
  • ✅ Files never leave your device
  • ✅ Instant conversion
  • ✅ Works on any browser and device

How it works

Each PDF file you add is read as a byte array in your browser. The pdf-lib library opens each document, copies all its pages into a new combined PDF document in the order you specify, and then generates the merged output file for download. No server is involved at any point.

Frequently Asked Questions

How many PDF files can I merge at once?
There is no enforced limit on the number of files. The practical limit depends on your device's available memory. Merging tens of documents with thousands of pages works fine on most modern devices.
Can I change the order of the PDFs before merging?
Yes — drag the file rows up or down to set the desired page order before clicking Merge.
Will the merged PDF preserve bookmarks, forms, and annotations?
Page content and embedded images are fully preserved. Some interactive elements like form fields and JavaScript actions may not be preserved, as pdf-lib focuses on page-level content.
Is there a file size limit?
No. Since all processing happens locally in your browser, the limit is your device's RAM. Most modern devices can handle hundreds of megabytes of PDFs without issue.

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