How to use the Merge PDF tool
- Choose your PDF files, or drag them onto the drop area. You can add more at any time.
- Arrange them: drag a file up or down, or use the arrow buttons. The first file in the list becomes the first pages of the merged PDF.
- Check the thumbnail and page count of each file. A file that is password-protected or damaged is flagged so you can remove it.
- Press Merge, then download the new PDF. Use the shortcuts underneath to compress it or fix page order next.
Worked example: a cover letter, a contract and an invoice
You need to send one file that holds a 1-page cover letter, a 3-page contract and a 2-page invoice. Add the three PDFs, then drag the cover letter to the top of the list so the order reads cover letter, contract, invoice.
- Pages in the result: 1 + 3 + 2 = 6 pages.
- Page 1 is the cover letter, pages 2 to 4 are the contract and pages 5 and 6 are the invoice.
- The contract was saved on A4 (595 x 842 points) and the invoice on US Letter (612 x 792 points); each page keeps its own size.
The merged file is named merged.pdf. If it is too big to email, send it straight to Compress PDF from the result box.
What merging keeps and what it changes
Merging copies every page of every file, in order, into a new document. Text, images, vector graphics and page sizes are preserved exactly, so a landscape page stays landscape and an A4 page next to a Letter page keeps both sizes. What the merged file does not carry over is document-level structure that only makes sense inside the original: bookmarks, interactive form fields, tagged-PDF accessibility structure and attachments. If you need those, merge in your PDF editor instead.
The new file gets fresh metadata (title, author and dates are not inherited), which is handy when you do not want the properties of the first document to leak into a combined report.
Tips for large merges
Merging copies pages in batches inside a background worker, so a 300-page job does not freeze the tab. The limit is your device memory: each file is read into memory once, so merging several hundred megabytes on a phone may fail while a laptop manages it. If a merge runs out of memory, merge in two rounds and then merge the two results. Compress scans first if they are huge; high-resolution scans are the usual cause of very large merged files.
Your files stay on your device
The PDFs you choose are read by code running in this page and merged in a background worker thread of your own browser. They are not uploaded, and there is no server involved in the merge at all. You can confirm it by opening your browser network panel while you merge, or by going offline once the page has loaded.
Frequently asked questions
Is there a limit on the number or size of files?
There is no limit set by this site. The practical limit is the memory of your device, because the files are held in memory while they are merged. Dozens of ordinary documents are fine on a laptop.
Can I merge password-protected PDFs?
Not directly. The library used here cannot decrypt files. Open the PDF in your viewer, enter the password, and save or print a copy without a password, then merge that copy.
Will bookmarks and form fields survive?
No. Pages, text and images are kept, but bookmarks, fillable form fields and tagged structure from the originals are not carried into the merged file. Fill and flatten forms first if their answers must appear in the merged file.
Does the order of the list matter?
Yes. Pages appear in the merged PDF in the same order as the files in the list, and each file keeps its own page order. Reorder before you press Merge.
Does it work on a phone?
Yes, on modern phone browsers, with the memory caveat for very large files. Tap Choose files to pick PDFs from your storage.