Merge PDFs

This tool joins several PDF files into a single document, in the order you set, directly in your browser. The merge engine is written in Rust and compiled to WebAssembly: your files are read from disk into the page's memory, combined there and handed back as a download, without any request to a server. It is the right default for lawyers and anyone assembling contracts, briefs, invoices or application packets, where the content of every page matters.

How to merge PDF files

1. Drop your PDF files on the tool, or click to select them. You can add more later with the Add more button.
2. Check the file list. Use the up and down arrows to move a file, and the cross to remove one.
3. When at least two files are in the list, click Merge PDFs.
4. The result panel shows how many files were merged and the output size. Click Download to save merged.pdf.

The first file in the list becomes the first pages of the output, the second file follows, and so on. Inside each file, pages keep their original order. Only files ending in .pdf are accepted by the drop zone.

Typical uses

• Application files: cover letter, CV, diplomas and references sent as one PDF, as many recruitment and rental portals require.
• Accounting: a month of invoices or receipts combined into a single document for your accountant or an expense report.
• Legal and admin packets: a contract with its annexes, or a signed form with its supporting documents.
• Scans done in several passes: a scanner that saves one PDF per batch of pages produces several files that belong together.

Limits and what to expect

• Number of files: 2 minimum, 20 maximum per merge.
• Size: each PDF can be up to 75 MB and 1,000 pages, with 300 MB and 2,000 pages in total.
• Bookmarks: the outlines (sidebar bookmarks) of the source files are not carried into the merged document. Page content, web links on the page and page sizes are kept.
• Mixed page sizes: an A4 file and a Letter file can be merged. Each page keeps its own size and orientation.
• Error reporting: if one file cannot be read (damaged, not really a PDF, or too large), the tool names that file so you can remove it and try again.

The merger copies the internal objects of each document instead of re-rendering pages, so text stays selectable, vector graphics stay sharp, and images are not recompressed. The output is compressed with Flate before download, which keeps it compact.

After merging: reorder pages, number them, trim

Merging works at the file level. To move individual pages, rotate a scanned page that came in sideways or delete a blank page, open the merged file in the PDF organizer. To add page numbers across the combined document, which helps when you refer to "page 14 of the annex", use page numbers and watermark. And to take a range of pages back out of a large file, use Split PDF.

Compared with desktop software

On macOS, Preview can merge PDFs by dragging thumbnails from one sidebar into another. On Windows there is no built-in merge, so people often turn to Adobe Acrobat (paid for this feature) or a command line tool such as qpdf --empty --pages a.pdf b.pdf -- out.pdf. These work well when they are available. This tool gives the same result on any device with a modern browser, including a locked-down work computer or a Chromebook, without installing anything and without sending the files to an online service.

Why merge without uploading

Merged PDFs are often the most complete version of a file: the whole contract with every annex, a full tax return, a medical history. Uploading them to a free web service means a copy exists, at least for a while, on infrastructure you do not control. Here the processing happens in your tab. You can verify it in the Network tab of your browser's developer tools: after the page and its WebAssembly module load, merging triggers no request. As our guide on merging PDFs without uploading them puts it, if a PDF leaves your browser, privacy becomes a promise instead of a property.

Frequently asked questions

How many PDFs can I merge at once?

Up to 20 files per merge, with a combined maximum of 300 MB and 2,000 pages. For more, merge in two rounds and then merge the results.

Can I change the order of the files?

Yes. Use the up and down arrows next to each file before clicking Merge PDFs. The list order is the page order of the output.

Can I reorder individual pages, not just files?

Not in this tool. Merge first, then open the result in the PDF organizer to move, rotate or delete single pages.

Will the merged PDF lose quality?

No. Pages are copied as they are, without re-rendering or image recompression. Text remains selectable.

Are bookmarks preserved?

No. The bookmarks panel of the source files is not carried over. The page content itself, including web links on the page, is kept.

Can I merge password-protected PDFs?

The tool has no password field. Remove the protection in the software that created the file first, then merge.

Are my files uploaded?

No. The files are read and combined inside your browser by a WebAssembly module. Nothing is sent to a server and nothing is stored after you close the tab.