How to merge PDF files (without uploading them)
Combine several PDFs into one document in the right order, keep quality intact and avoid the common pitfalls with scans, forms and protected files.
· 2 min read
Merging PDFs is one of the most common document tasks: a job application with a CV, cover letter and diplomas, a year of invoices for your accountant, or a report assembled from several authors. Here is how to do it cleanly.
Step by step
- Open the Merge PDF tool and drop all your files at once.
- Put them in the order you want the reader to see them, using the up and down arrows.
- Click Merge PDF and download the single file.
The whole operation happens in your browser, so confidential documents never leave your device.
Check the page order before you send it
Merging keeps the page order of each file. If one of the documents was scanned in the wrong order, or you need to move a single page (for example a signature page) somewhere else, run the merged file through Organize PDF afterwards: you can move, duplicate or remove individual pages with thumbnails.
Keep the quality — and the file size — under control
A good merge copies pages without re-compressing them, so text stays selectable and images keep their resolution. The flip side is that the merged file is roughly the sum of the originals. If it's too big for an email or an upload form:
- For scans and photo-heavy PDFs, use Compress PDF in strong mode. It turns pages into optimised images and often divides the size by 5 to 10.
- For text documents, the size usually comes from embedded images; compress those images before creating the PDFs.
Add page numbers last
If the merged document will be printed or discussed in a meeting, add page numbers after merging with PDF page numbers so the numbering runs continuously across all parts.
Common problems
“This PDF is password-protected.” Encrypted PDFs can't be combined until the protection is removed with the software that created them (or by the person who knows the password).
Forms lose their fields. Interactive form fields are not always preserved when pages are copied into a new document. Fill and flatten forms (print to PDF) before merging.
Mixed page sizes. Merging A4 and Letter pages is fine — each page keeps its own size — but printed output may look inconsistent. That's normal.