PDF Merging Tips
File order matters
Drag files into the order you want them merged before clicking Merge. The order you upload them is the order they appear in the final PDF.
Combine scanned documents
Merging works well for combining scanned pages where each page is a separate PDF file. Upload all pages, arrange them, then merge into one document.
Large file merging
Merging runs entirely in your browser, so your PDFs are never uploaded to any server, your files stay private on your device.
Password-protected PDFs
PDFs with password protection cannot be merged without entering the password first. Remove password protection using a PDF editor before merging.
How to Merge PDF Files in Your Browser
Add your PDF files
Drag your PDFs onto the upload area or click to browse and select them. The tool reads each file and shows its name, size, and exact page count so you can confirm you loaded the right documents before combining.
Arrange the order
Drag any file by its handle to set the sequence you want. The merged PDF follows the top-to-bottom order of the list. Use the remove button to drop any file you added by mistake before continuing.
Merge and download
Click Merge PDFs to combine every page into one document, then click Download Merged PDF to save it as merged.pdf. All work happens locally with pdf-lib, so your files stay on your device throughout.
What the Merger Keeps and Changes
Merging copies the pages from each PDF into a brand new document in the order you set. Here is what stays the same and what is affected so you know what to expect from the output.
| Aspect | Before Merge | After Merge |
|---|---|---|
| Pages | Spread across separate files | Combined into one file, in your chosen order |
| Page layout and fonts | Original per file | Preserved exactly, no re-rendering |
| Images and vectors | Embedded in each PDF | Copied without recompression |
| File size | Sum of all inputs | Roughly the sum, no compression applied |
| Encrypted or password PDFs | Locked | Not supported, remove protection first |
| Output name | Individual names | Single file saved as merged.pdf |
When This Merge Tool Is the Right Choice
Combining whole documents
Ideal when you want to join two or more complete PDFs, such as a cover letter and a resume, or several scanned pages, into one file in a specific order.
Keeping originals intact
Choose this when you need the merged result to preserve the original formatting, fonts, and images without any quality loss, since pages are copied rather than re-rendered.
Working with sensitive files
A good fit when you prefer that documents are not uploaded. Merging runs in your browser with pdf-lib, so the files stay on your device during the process.
Use a different tool instead
If you need to remove or extract single pages, use the Split PDF tool. To shrink the result, run a PDF compressor afterward, since merging does not reduce file size.
Common Problems and Fixes
The merge button does nothing
You need at least two PDF files in the list to merge. Add another file, then click Merge PDFs. A single file cannot be merged on its own.
A file shows zero pages or fails to load
This usually means the PDF is password-protected, encrypted, or damaged. Remove the password in a PDF editor, then re-add the file. Confirm the file actually opens in a normal PDF viewer first.
The pages came out in the wrong order
The output follows the order in the file list, not the order you selected files in. Drag each item by its handle into the correct position before clicking Merge PDFs.
Merging is slow or the tab freezes
Very large PDFs or many files are processed using your device memory, which can take a few seconds. Close other heavy tabs, merge in smaller batches, and let the status text finish before downloading.