Merge PDF Files
Combine several PDF files into one document, in the order you choose.PDF & DocumentsMerge PDF
Combine several PDF files into one document, in the order you add them. Files are read locally with pdf-lib.
About this tool
Merging PDFs usually means sending confidential documents to a third-party server. This tool does it on your device instead: a JavaScript PDF library reads each file, copies its pages into a new document in the order you set, and gives you the result as a download.
How to use the Merge PDF tool
- Add your PDFs. Select two or more PDF files. Only files beginning with a valid PDF header are accepted.
- Set the order. Use the up and down controls to arrange the files. Pages are appended in exactly that order.
- Merge and download. Click Merge PDFs, then use the download button that appears. The combined document is built locally.
Supported formats
Input
- PDF files (.pdf)
Output
- A single merged PDF
Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.
Frequently asked questions
Is there a file size or page limit?
There is no hard page limit, but very large documents are constrained by your device's available memory because the whole file is held in the browser tab.
Are encrypted PDFs supported?
No. Password-protected or heavily encrypted documents cannot be opened reliably in the browser and are rejected with a clear message.
Will the output lose quality?
No. Pages are copied into the new document rather than re-rendered, so text, vectors and images keep their original data.
Do my documents leave my device?
No. The PDF library is bundled with the page and the merge happens entirely in your browser.
Privacy
Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.
No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.
Known limitations
- Encrypted or password-protected PDFs are not supported.
- Very large files are limited by the memory available to the browser tab.
- Interactive form fields and digital signatures are not preserved when pages are copied.
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