Merge PDF files into one document
Open your first PDF, then append as many others as you need. Matching Sox PDF copies every page of each added file onto the end of the open document, in the order the files were selected, and builds the combined file with the open-source pdf-lib library inside your browser tab.
Fillable forms in the files you append are flattened, so their current values become fixed text on the page. Need a different order after joining? Switch to Organize pages and move any page earlier or later before you download.
Free forever. No signup. No watermark. Your files never leave your device.
How to merge PDF
- Choose Open a PDF and pick the document that should come first.
- Select Merge PDFs in the left menu.
- Press ＋ Add PDFs and choose one or more files. They are added in the order you select them.
- Optional: use Organize pages to rearrange the combined pages.
- Press Download PDF ↓ to save the merged file.
Questions
How many PDFs can I merge at once?
You can select several files in one go and repeat ＋ Add PDFs as often as you like. Each added file must be under 100 MB so your browser does not run out of memory.
In what order are the files combined?
Appended files go after the pages already open, in the order you selected them. Afterward you can reorder single pages with Organize pages.
What happens to form fields when I merge?
Form fields in appended files are flattened. Their current values become fixed text and can no longer be edited as fields.
Are my files uploaded to combine them?
No. Merging runs on your device inside the browser. Nothing is sent to a server.