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FilesKit

Merge PDF files

Combine two or more PDF files into a single document, in the order you choose. The merge happens in your browser, so your files are not uploaded to a server.

PDFProcessed in your browser
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Features

  • Page previews

    Every page of every file is shown as a thumbnail, with the file size and page count, so you can check what you are combining.

  • Reorder whole files

    Move files up or down until the order is right. The merged document follows the order shown.

  • Up to 30 files at once

    Add two to thirty PDFs in one go, by dragging them in or choosing them from your device.

  • Pages are copied as they are

    Text, images, fonts and annotations come along unchanged. Nothing is recompressed or rasterized.

How to use Merge PDF

  1. Choose at least two PDF files or drop them onto the page.
  2. Check the page thumbnails and use the arrows to put the files in the order you want.
  3. Select Merge PDF and wait for the progress bar to finish.
  4. Download merged.pdf.

Supported formats

AcceptsPDF
ProducesPDF

Files are recognised by their content, not their file extension.

Limits and things to know

  • You can merge 2 to 30 files, up to 100 MB each and 300 MB in total. Phones and tablets have less memory, so large files may fail there.
  • Password-protected PDFs are not supported. Remove the password in the program that created the file, then try again.
  • The result is a new document: bookmarks, document-level metadata and links between form fields in the source files are not kept.
  • Damaged files are reported by name and must be removed before merging.

Privacy and processing

The merge runs in a Web Worker inside your browser, using the open-source pdf-lib library. Your files are read from your device into the browser’s memory and the merged PDF is created there. FilesKit has no server that receives or processes files. Only the tool’s own code is downloaded from this website, and only when you open the page.

Common uses

  • Combine scanned pages

    Join separate scans of one document into a single file before sending or archiving it.

  • Assemble an application

    Put a form, a cover letter and supporting documents into one PDF for an upload that accepts a single file.

  • Add a cover page

    Put a title page or an invoice summary in front of an existing report.

  • Bundle monthly records

    Merge bills, receipts or statements for a period into one document.

How this differs from other approaches

Many online mergers upload your files to a server and return the result, which adds waiting time and means the files leave your device. FilesKit merges in the browser instead, so there is no upload step and no account. Desktop PDF programs can handle very large files and keep more document structure, such as bookmarks; use one if you need that.

Frequently asked questions

Are my PDF files uploaded anywhere?

No. The files are processed by code running in your browser. FilesKit has no server that receives them.

Does merging reduce the quality of my PDFs?

No. Pages are copied as they are, without recompressing images or converting text, so the content looks the same as before.

Can I merge password-protected PDFs?

Not directly. These files are rejected with a message. Remove the password first, then merge the unlocked copies.

Will bookmarks and form fields survive the merge?

Bookmarks, document-level metadata and form-field relationships are not carried over, because the result is a new document made of the copied pages.

Does it work on a phone?

It works in current mobile browsers, but a phone has far less memory than a computer, so keep the total size small.

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