About the PDF Merger
The PDF Merger joins two or more PDF files into a single document, in the order you select them. It is handy when you have a cover letter and a CV saved separately, several scanned receipts you need to send as one attachment, or chapters of a report exported from different programs.
The merge runs inside your browser using the open-source pdf-lib library. Your files are read from your device and the combined PDF is built in memory, so nothing is sent to a HandyHex server. The library itself is fetched from a public CDN the first time you use the tool, so you need an internet connection for that first load.
How to use it
- Click Select PDFs or drag and drop at least two PDF files onto the page. Use Add more to keep adding files.
- Check the list and the preview on the right. Drag the handle or use the arrows to reorder, sort by name, or remove any file.
- Password-protected PDFs cannot be merged, so the preview will say if a file cannot be read.
- Press Merge and download. A single merged PDF is saved to your device.
Tips for a clean merge
Name your files with numbers (01-cover.pdf, 02-report.pdf) and select them together so the order is predictable. If the order is wrong, simply run the merge again with a different selection.
Very large files (hundreds of pages or many megabytes) use your device's memory. If the browser slows down, merge in smaller groups and then merge the results.
Merging keeps the pages as they are. It does not reduce file size; use the PDF Optimizer if you need to re-save the result.
Real-world examples
Job application pack. Many employers accept one PDF only. Save your cover letter, CV and certificates as separate PDFs, number them 01, 02, 03, select all three, and you have a single file named the way you want.
Expense claim. Photograph each receipt, turn the photos into PDFs with Images to PDF, then merge them with the claim form on top. Finance teams get one attachment instead of fifteen.
Study notes. Combine lecture slides exported from different courses into one searchable revision file.
Common mistakes
Selecting files in the wrong order is the most frequent problem, so check the first and last page of the result. Another is merging a password-protected file, which fails because the tool cannot read it. Finally, remember a merged PDF is as large as its parts added together, so a pack of scans can exceed an email limit.
How it works
The tool reads each file as raw bytes, parses its page tree with the pdf-lib library, copies every page into a new empty document in your chosen order, and writes the result out as a new file. No server is involved, which is why large merges depend on your device's memory instead of an upload speed.
Frequently asked questions
Are my PDFs uploaded anywhere?
No. The merge happens in your browser. Only the pdf-lib code library is downloaded from a CDN.
Can I merge password-protected PDFs?
No. Remove the password with the program that created the file first, then merge.
Is there a page or file limit?
HandyHex sets no limit, but your device memory does. Merge in batches if a very large job fails.