Merge PDFs

stack files into one · in your browser

Drop a stack of PDFs and stitch them together into a single document. Reorder before merging — the merged file follows the order you set.

When to use this tool

Reach for the merge tool when you have two or more PDFs that need to live as one — a folder of single-page invoices that should be archived together, a multi-part scanned report that came back from the scanner as separate files, exhibits A through F to attach to a contract, or a combined "submission packet" you want to email as one document. The tool concatenates them losslessly: nothing is re-rendered, recompressed, or downsampled.

Step by step

1. Drop your PDFs into the drop zone — or click it to open a file picker. You can drop them one at a time or all at once.
2. Reorder using the ↑ / ↓ buttons on each row. Row 1 becomes the first page of the merged file. The thumbnail next to each filename helps you confirm you're moving the right one.
3. Remove a file you didn't mean to add with the × button. Re-drop it if you want it back, or drop it again to include it twice.
4. Click "Merge & download" — the merged file appears in the output list with a thumbnail of page 1. Click Download to save it.

Common use cases

• Receipts and expenses — combine a month of one-page receipts into a single PDF before submitting to your finance team or accountant.
• Multi-page scans — old document feeders sometimes save each scan as a separate file; this tool joins them in the order you scanned.
• Contracts with exhibits — main agreement + appendix + exhibits A/B/C as one document for signing.
• Reading lists — bundle several short articles or whitepapers into one e-reader-friendly file.
• Job applications — CV + cover letter + portfolio + references into one PDF for the recruiter to download.
• Class handouts — combine slides and worksheets into a single hand-out PDF for students.

Common mistakes

• Wrong order. Drop order is preserved — but it matches the OS's drag order, which is alphabetical, not the order you visually picked the files. Always check the row order before merging.
• Forgetting a page is included twice. Dropping the same file again adds another copy. Watch the row count.
• Merging password-protected files. Files with a user (open) password cannot be opened in the browser; you'll see an error. Strip the password first via Lock / unlock if you have it.
• Expecting "compression." The merged file size is roughly the sum of the inputs — pdf-lib does not recompress streams.

FAQ