How to merge PDF files
- Drop your files on Drop PDF files here or click to choose, or click it and select several PDFs at once. You can add more later.
- Check the list. Each row shows the page count and size. Use Move up and Move down, or drag a row, to set the order. Remove takes a file out.
- Type a Name of the merged file if you do not want
merged.pdf. - Click Merge PDFs, then Download. Merge PDFs stays off until the list has two files.
How the merge works
The page loads the open-source pdf-lib library and creates an empty PDF. For each file in your list it copies every page object, with its text, fonts, images and vector drawing, into the new document (copyPages). Nothing is redrawn or recompressed, so quality does not change, and each page keeps its own size and rotation. Everything runs in your browser and the files are not uploaded.
Worked example with the sample files
Click Try two sample PDFs. The list shows sample-a.pdf with 2 pages and sample-b.pdf with 3 pages, so Files reads 2 and Total pages reads 5. After Merge PDFs you see "Merged 2 files into one PDF with 5 pages" and a download named merged.pdf. Pages 1 and 2 are sample A, and pages 3 to 5 are sample B. Move sample B up first and the order flips.
Limits and edge cases
- Password-protected or restricted PDFs are refused with a message, because the merge cannot read them. Save an unlocked copy with the PDF password remover and add that.
- Bookmarks (the outline panel) are not carried over. Links between pages of the same file are re-pointed to the right merged page, and web links are kept.
- Fillable form fields may stop being editable, and digital signatures no longer validate, because the result is a new file.
- Titles and authors from the originals are not copied. The work happens in memory, so a job of several hundred megabytes can be slow or fail on a phone. Merge in smaller batches, then shrink the result with the PDF compressor.
- This tool orders whole files. To use only some pages of a file, cut them out first with the PDF splitter. To turn photos into PDF pages, use image to PDF.
PDF merging questions people ask
How do I merge PDF files without uploading them?
Choose the files on this page and click Merge PDFs. The work is done by JavaScript in your own browser tab, so the files never leave your device. Closing the tab discards them.
Does merging PDFs reduce quality?
No. Pages are copied into the new file as they are, with no re-rendering or recompression, so text stays sharp and images keep their resolution. The merged file is roughly the combined size of the originals.
Can I merge password-protected PDFs?
Not directly. A locked file is skipped with a message. Save an unlocked copy first, for example with the PDF password remover on this site, then add that copy to the list.
Why did my bookmarks disappear after merging?
Bookmarks belong to the original document and are not copied when pages move into a new file. Links between pages are kept and re-pointed, but the outline panel will be empty.
How do I merge only some pages of a PDF?
Split first. Use the PDF splitter to extract the pages you want into their own file, then add that file here together with the others.
Method reference: pdf-lib documentation.