Batch merge PDF
Drop every PDF at once. Files whose names differ only by the number at the end are merged together, one PDF per group, in the right order.
Groups found
These names have nothing in common, so every file would come out on its own. The number has to be at the end of the name, as in invoice-001.pdf.
How to merge PDFs in batches
- Choose every PDF at once — a whole month of invoices if you like.
- Check the groups it found: the number at the end of each name is dropped, and what is left is the group.
- Press the button. Each group is merged in the order of those numbers.
- You get a ZIP with one PDF per group, each named after what its files share.
What counts as a group
The extension goes first, then a number at the end of the name, with or without a separator: -001, _2, (3), .4 or plain 07. Whatever is left is the group, so AAAA20260921-001.pdf and AAAA20260921-002.pdf both belong to AAAA20260921 and come out as AAAA20260921.pdf. Names that differ only in capitals go together. A file with no number at the end is a group of its own and is copied as it is.
The order inside each group
By the number, read as a number: 2 comes before 10, and 007 is 7. When two files in a group have no number to compare, they follow their names. The groups themselves come out in alphabetical order, which is why dates written as 2026-09-21 sort themselves correctly.
It reads names, not contents
Nothing inside the files is looked at, so a document saved under the wrong name lands in the wrong group. That is why the groups are listed before anything is merged: check them, and if a name is off, rename the file and drop the folder again.
Is it private?
Yes. Everything runs inside your web browser, using your own device. Nothing is uploaded to any server, so your documents stay completely private. How does this work without uploading?
Frequently asked questions
How many files can I drop at once?
As many as your device can hold in memory — a few hundred is normal. They are merged one group at a time, and a group that fails (a password-protected file, a damaged one) is reported and skipped: the rest still download.
Are my files uploaded?
No. The merging happens in your browser, the same as every tool here. You can disconnect from the internet after the page loads and it still works.
What if I only need one merged file?
Use Merge PDF: you choose the files, drag them into the order you want and get a single PDF. This tool is for when the order and the grouping are already in the names.