About the Merge PDF
Merge PDF combines several PDF files into a single document. Add the files, put them in the order you want and, if you only need part of a file, type the pages to include – for example 1-3, 5. The pages are copied into one new PDF in exactly that order.
It is handy for assembling a job application from a CV, cover letter and certificates, collecting monthly invoices into one file for your accountant, or joining scans that were saved as separate files.
The files are read and written by JavaScript (the open-source pdf-lib library) in a background thread of your browser. Nothing is uploaded, so confidential documents stay on your device.
How to use it
- Click “Choose PDF files” or drag PDF files onto the box. You can add more later with “Add more PDFs”.
- Check the list: every file shows its size and number of pages. Files that cannot be used, such as password-protected PDFs, are marked in red – remove them with the trash button.
- Change the order by dragging the handle on the left of a file, or with the up and down arrow buttons. Files are merged from top to bottom.
- Optionally type the pages to include for a file, for example 1-3, 5 or 8- (page 8 to the end). Leave the field empty to include every page.
- Click “Merge PDFs” and wait for the progress bar to finish.
- Click “Download merged.pdf” to save the combined document.
Features
- Page ranges per file: Include only the pages you need from each file. Pages are added in the order you type them, so “3, 1, 2” also changes their order.
- Reorder by drag and drop or buttons: Move files with the mouse, by touch on a phone, with the arrow keys on a focused handle, or with the up and down buttons.
- Up to 50 files: Merge up to 50 PDFs at once, each up to 200 MB and up to 500 MB in total.
- Pages stay as they are: Pages are copied, not converted: text stays selectable and searchable, images are not re-compressed, and page sizes and rotation are kept.
- Private by design: All processing happens locally in a Web Worker in your browser. No account, no upload, no watermark.
Examples
Job application
Add cv.pdf, cover-letter.pdf and certificates.pdf, drag the cover letter to the top, merge, and attach the single merged.pdf to the online application form.
Only the pages that matter
For a 12-page contract, enter 1-3, 12 to keep the first three pages and the signature page, add the appendix with the field left empty, and merge both into one file.
A year of invoices
Select all twelve monthly invoice PDFs at once in the file picker, check that they are listed from January to December, and download one file for your tax return.
Limitations and notes
- Password-protected and encrypted PDFs cannot be merged – this includes PDFs that open without a password but restrict editing or printing. Save an unprotected copy in a PDF reader first.
- Bookmarks (the outline panel in PDF readers) and document properties such as the title of the source files are not carried over to the merged file.
- Form fields are no longer fillable in the merged file (their current appearance usually stays visible), and digital signatures are not valid because the document has been rewritten.
- Links that jump to another page keep working when that page is part of the merged file; links to pages you left out are removed.
- Everything happens in your device’s memory, which limits very large files, especially on phones and tablets. The merged file is roughly as large as the selected pages combined – it is not compressed.
Frequently asked questions
How many PDF files can I merge at once?
Up to 50 files, each up to 200 MB and 500 MB in total. If you need more, merge them in batches and then merge the resulting files.
Can I merge only some pages of a PDF?
Yes. Type the pages into the “Pages” field next to the file, for example 2-4, 7 or 10- for page 10 to the end. Leave it empty to include the whole file.
Why is my file marked as password-protected?
The PDF is encrypted. Some files open without a password but are still encrypted to restrict printing or editing, and those cannot be processed either. Open the file in a PDF reader, enter the password if needed, and save or print it as a new PDF – then add that copy.
Does merging reduce the quality?
No. Pages are copied as they are, so text remains text and images are not re-compressed. The merged file looks the same as the originals.
Are my files uploaded to a server?
No. The files are processed by JavaScript in your browser and the merged PDF is created on your device. You can even disconnect from the internet after the page has loaded.
Can I merge PDFs on my phone?
Yes. Drag files by the handle or use the arrow buttons to reorder them. Phones have less memory than computers, so very large files may fail on a phone.