Merge PDFs
Combine multiple PDF files into a single document. Your files never leave your device.
I end up using this more than almost any other tool on the site. Scanners produce one PDF per page. Clients send contracts in three pieces. Reports come in sections from different people. The need to stitch PDFs together comes up constantly, and doing it without uploading sensitive files to a third-party server matters.
Everything on this page runs locally in your browser. No file is uploaded to any server at any point.
How the merge works
When you add files and click Merge, the tool reads each PDF using the browser's FileReader API and passes the binary data to PDF-lib, an open-source JavaScript library. PDF-lib creates a new empty document, then copies every page from each of your source files into it in the order you specified. The merged document is serialized back to binary and downloaded to your device.
What gets preserved
PDF-lib copies pages at the structural level, not by rendering them as flat images. That means the merged document keeps selectable text, embedded fonts, vector graphics, images at original quality, existing hyperlinks, and page-level annotations. What doesn't carry over: cross-document outline entries, interactive form fields, and JavaScript embedded in source files. For everyday merges, contracts, reports, scanned documents, none of that matters.
Controlling page order
The order of files in the list is the order of pages in the output. Drag items to reorder before merging. The × button removes individual files if you added something by mistake.
File size
The merged PDF will be approximately the sum of the input file sizes. PDF-lib does not apply additional compression. If the result is larger than needed, run it through the Compress PDF tool afterward.
Privacy
No file leaves your browser. No server receives your data. No account is required. This matters for legal documents, medical records, financial statements, files you would not want sitting on a stranger's server. With this tool, they never do.
Common situations where this helps
Scanned pages from a flatbed scanner
Scanners frequently produce one PDF per page. If you scanned a 12-page document and got 12 separate files, add them all here, drag them into page order, and merge. Done in a few seconds.
Contract packages
A signed contract often arrives as the main agreement, an exhibit, a signature page, and an amendment. Merging them into one file makes storage and reference far cleaner than a folder of related pieces.
Report sections
When different team members export their sections separately, merging here assembles the final document without reformatting or copy-paste work.
Submission requirements
Government agencies, courts, and grant applications often require all supporting documents combined into a single PDF. This handles that preparation without any installed software.
Frequently asked questions
Is there a file limit?
No hard limit. You can add as many files as your device's memory can handle. Dozens of typical documents merge without issue.
Will the merged PDF be searchable?
Yes, as long as the source files contained selectable text. Scanned documents that were never OCR'd will remain non-searchable, the original pages contain images of text, not actual text characters.
What if one file is password-protected?
Locked PDFs cannot be read by the browser without the decryption key. Remove the password before adding the file here.
Can I merge a PDF with a Word document or image?
This tool merges PDFs only. Convert other formats to PDF first, most word processors let you export to PDF, and the JPG to PDF tool handles image files.