Merge PDF files
Add your PDFs, put them in order and join them into a single file. It runs in your browser and nothing is uploaded.
Free · no signup Runs in your browser
How do I merge PDF files?
Add the PDFs, put them in the order you want with the arrows and press Merge PDFs. The pages of each file are copied, in order, into one new PDF that is saved to your downloads. It all happens in your browser, so private documents never leave your device, and there is no watermark.
Why merge PDFs
Applications, claims and legal packages often ask for everything in one PDF: a form, a letter, a few receipts and an identity document, each arriving as a separate file. One file is easier to send, easier to file and harder to lose a page from.
The tool copies every page of each file, in the order shown, into a new document. The pages keep their size, text and pictures, and text stays searchable. Bookmarks and interactive form fields from the originals may not be carried over, so for fillable forms merge a flattened copy. The files are read on your device and the merged file is built in your browser, so there is no upload wait and nothing to trust a server with.
It runs in your browser. Your files are never uploaded, and there is no watermark or sign-up.
How it works in detail
Each PDF you add is opened in your browser with pdf-lib. When you press Merge PDFs, every page of each file is copied, in the order shown in the list, into a new PDF, together with what the pages use (text, fonts and pictures). Page sizes and rotation are kept, so a file with A4 pages and one with Letter pages keep their own sizes in the merged file. The new document is saved as merged.pdf. Because only the pages are copied, bookmarks, the document outline and interactive form fields may not carry over to the merged file. Nothing is uploaded, and there is no watermark.
How to use it
- Add your PDFs: drop them on the box, or press it to choose several.
- Use the arrows to put the files in the order you want. The first file's pages come first.
- Press Merge PDFs and wait for the total page count.
- Download merged.pdf and check the order of the pages and the size of the file.
- To reorder or remove individual pages afterwards, use the rearrange or delete pages tools.
What changes and what stays the same
What the tool does to your file, and what it leaves alone.
| Aspect | What happens |
|---|---|
| Pages and their order | All pages of every file, in the order of the list |
| Page sizes and rotation | Kept as they are in each file |
| Text, fonts, pictures | Copied with the pages, so the result is searchable if the originals were |
| Bookmarks, outline, form fields | May not carry over |
| File size | Roughly the sum of the files, a little less when they share fonts |
| The original file | Never changed: the tool builds a new file and the original stays where it is |
| Privacy | The PDF is read on your device and is not uploaded; there is no account and no watermark |
When to use it
- Sending an application with several documents as one file
- Joining scanned pages that were saved separately
- Building a single report from several sections
- Combining receipts for an expense claim
Problems you may run into
Most problems come from the file itself, not from the tool.
| What you see | Likely cause | What to do |
|---|---|---|
| 'This PDF is password-protected' | The file is encrypted, so the browser cannot read it | Remove the password in the program that made it (or open and print to a new PDF), then try again |
| 'This file could not be read as a PDF' | The file is damaged, or is not really a PDF (it was only renamed) | Open it in a PDF viewer to check; if it opens there, re-save it as a new PDF and try again |
| The merged file is very large | Every file's pictures and fonts are copied in | Compress the merged PDF with the compress PDF tool |
| Files are in the wrong order | The list order is the page order | Move files with the arrows and merge again |
| Page sizes look uneven when printing | The files have different page sizes | Print with 'fit to page', or make the sizes match first |
| The browser slows down or stops | A very large PDF (hundreds of megabytes) or an old phone is out of memory | Close other tabs, try a computer, or split the file first with the split tool |
Mistakes it helps you avoid
- Sending pages in the wrong order: check the order before merging.
- Merging a password-protected file: remove the password first.
- Expecting form fields to stay fillable after merging.
- Making a file too large to email: compress the pictures first if the result is big.
How it works
Your PDF is read and rewritten inside your browser.
1. Each PDF you add is opened in your browser with pdf-lib.2. Every page of each file is copied, in the order shown, into a new PDF.3. The new PDF is saved and offered as merged.pdf. Nothing is uploaded.
The merge copies each page and the content it uses (text, fonts, pictures) into the new file. Page sizes and rotation are kept, so files with different page sizes keep their own sizes. Bookmarks, document outlines and interactive form fields may not carry over. Very large files are limited by your device's memory.
Example: three documents into one
You have a 2-page form, a 1-page letter and a 4-page report.
- Orderform.pdf, letter.pdf, report.pdf
- Pages2 + 1 + 4 = 7
One merged.pdf with 7 pages, in that order
Use the arrows to change the order before you press Merge.
Terms on this page
- Merge
- Joining the pages of several PDFs into one file.
- Page tree
- The structure inside a PDF that lists its pages in order.
Common questions
Is it free, and is there a watermark?
Yes, it is free, with no watermark, no sign-up and no limit on the number of files.
Is my PDF uploaded?
No. Your browser reads the file on your own device, changes it and saves the result. Nothing is sent over the network.
Can it open a password-protected PDF?
No. Remove the password first in the program that made it or in a PDF viewer, then try again.
Can I change the order of the files?
Yes. Use the up and down arrows next to each file before you merge.
Will the text still be searchable?
Yes. The pages are copied as they are, so text stays selectable and searchable.
What to work out next
Where these numbers come from
- pdf-lib — create and modify PDF documents in any JavaScript environment (MIT licence) The open-source library used to read and write the PDFs in your browser.
- Adobe — PDF 32000-1:2008 (ISO 32000-1), the PDF specification The page tree, page rotation and file structure of a PDF.
- MDN Web Docs — Using files from web applications How a page reads a file you choose without uploading it.
Last verified 2026-10-25 The method on this page is checked against the sources above at least once a year. Spotted something out of date? Tell us and we will fix it.
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