Merge PDF Files
Combine multiple PDFs into one file, entirely in your browser. No upload, no watermark, no signup.
Built with pdf-lib (MIT), self-hosted.
How to use this tool
- Select two or more PDF files.
- Click Merge & Download.
- Your merged.pdf downloads — nothing was uploaded.
Combine multiple PDFs into one file, entirely in your browser. No upload, no watermark, no signup.
How it works
This tool combines multiple PDF files into a single PDF document, entirely within your browser. No files are uploaded to a server, which makes it safe to use with confidential documents such as contracts, financial statements, or medical records.
Select or drag-and-drop two or more PDF files. The tool displays them in a list you can reorder by dragging before merging. Click Merge and the combined PDF is generated in memory and offered as a download — no watermarks, no registration required.
Common uses include assembling a multi-chapter report, combining scanned pages into one document, packaging supporting documents together before emailing, and merging monthly bank statements into an annual file.
The merge preserves the original content of each PDF. Page dimensions, embedded fonts, and existing content within each file are retained in the output.
Worked example
Combine three monthly invoices into one PDF
- Click Add Files and select January.pdf, February.pdf, and March.pdf.
- Drag the files into chronological order if they appear out of sequence.
- Click Merge PDFs.
- Download the resulting combined file.
A single PDF containing all three invoices in order, ready to email or archive.
Common mistakes to avoid
- Not reordering the files before merging, resulting in sections appearing in the wrong sequence.
- Attempting to merge password-protected PDFs — these must be unlocked first.
- Merging many large high-resolution scan PDFs at once, which can exhaust browser memory on devices with limited RAM.
Key terms
- Portable Document Format — a file format that presents documents with text and graphics consistently across devices.
- Page order
- The sequence in which pages from each source PDF appear in the merged output; controlled by the order of files in the list.
- In-browser processing
- The merge operation runs using JavaScript in your browser tab, so no data passes over the network.
Frequently asked questions
- Are my PDFs uploaded to a server?
- No — merging happens locally with pdf-lib; files never leave your device.