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How to merge PDF files

Invoices, contracts, supporting documents… Combining multiple PDFs into one document is a daily need. This guide shows you how to do it in seconds, without installing software and without uploading your documents to a server.

Common use cases

  • Administrative file. Gather proof of address, ID, and bank details into one PDF for an online application.
  • Project report. Assemble different sections written by multiple collaborators.
  • Portfolio. Combine visuals and text into a single presentation document.
  • Accounting. Merge monthly invoices into one file for the accountant.

Tutorial: merge PDFs with Filzy

1

Open the merge tool

Go to Merge PDF.

2

Add your PDFs

Drag and drop all the PDF files you want to combine. You can also click to browse your device. There's no limit on the number of files.

3

Rearrange the order

Files appear in the order they were added. Drag thumbnails to change the order if needed. The first file will become the first pages of the final document.

4

Merge

Click "Merge". Processing happens locally in your browser. Even PDFs with dozens of pages merge in seconds.

5

Download the result

Your merged PDF is ready. Download it in one click. Your original files are not modified.

Other useful PDF tools

Filzy offers a complete suite of PDF tools that work great with merging:

  • Organize PDF. Reorder, delete, or duplicate pages in an existing PDF.
  • Compress PDF. Reduce the size of the merged PDF if it's too large.
  • Number pages. Add page numbers to the final document.
  • Protect PDF. Add a password if the document contains sensitive information.
  • Watermark PDF. Add a "Confidential" watermark or your logo.

Practical tips

  • Name your files well. If you're adding 10 PDFs, explicit names (invoice-january.pdf, invoice-february.pdf…) make reordering easier.
  • Check orientation. A landscape PDF inserted into a series of portraits can be surprising. Use Rotate PDF if needed.
  • Compress after merging. Merging preserves original quality. If the result is too heavy, run it through the PDF compression tool.

Your documents stay confidential

Merging happens entirely in your browser. No PDF is sent to a server. This is especially important for sensitive documents: invoices, contracts, IDs.