Free Online PDF Merge Tool

Combine multiple PDFs into one file. Reorder pages with drag and drop.

PDFs never leave your browser — merged with pdf-lib

Loading PDF engine…

Drop PDFs here or click to browse

PDF files only · Select multiple at once

Minimum 2 PDFs required

How to Merge PDF Files Online

Combining several PDF documents into one file is a common task — assembling a report from separate sections, packaging supporting documents together, or stitching chapters of an e-book. This tool handles it entirely in your browser using the open-source pdf-lib library. No files leave your device.

Click Browse or drag your PDF files into the drop zone. You can add as many as you need.
Use the ↑ / ↓ buttons or drag the rows to arrange the files in the order they should appear in the final document.
Click Merge & Download PDF. The merged file downloads instantly as merged.pdf.

What Gets Preserved During a Merge?

The pdf-lib library copies the rendered page content — all text, images, vectors, and annotations (including clickable hyperlinks) — faithfully from each source document into the output. What is not preserved: document-level bookmarks (the outline / table of contents sidebar), interactive form fields, digital signatures, and embedded JavaScript. For everyday document workflows these limitations rarely matter. If you need to preserve a full bookmark tree, consider using Adobe Acrobat or PDF24.

Tips for a Clean Merge

Check page orientation first. If some source PDFs are landscape and others are portrait, they will merge correctly but the output will mix orientations. Rotate pages in the source documents before merging if uniformity matters.
Remove password protection first. Encrypted PDFs cannot be loaded by this tool. Open them in the original application and re-save without a password, or use a trusted PDF unlocker tool.
Keep an eye on file sizes. Very large PDFs (100 MB+) will work but require more browser memory. On devices with limited RAM, consider splitting a large merge job into two smaller ones and then merging those outputs.

How to Use PDF Merge

1

Add your PDF files

Click Add PDFs or drag files onto the drop zone. You can add as many PDF files as needed — there is no limit.
2

Reorder files

Drag the file cards to reorder them. The merged PDF will follow the order shown on screen.
3

Merge and download

Click Merge PDFs. Your browser combines the files entirely locally and prompts you to download the merged document.

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Frequently Asked Questions

There is no hard limit enforced by this tool — you can add as many PDFs as you like. The practical limit is your device's available memory. Very large PDFs (hundreds of megabytes) or dozens of files may slow down older devices. For most everyday use cases (merging 2–20 typical documents), performance is instant.

Links and annotations within pages are preserved. However, document-level bookmarks (outline / table of contents) and interactive form fields are not currently carried over into the merged output — only the page content is copied. If you need to preserve complex PDF features, use a dedicated desktop tool like Adobe Acrobat or PDF24.

No. This tool cannot open or process encrypted or password-protected PDFs. If you try to add an encrypted PDF, it will show an error. You must remove the password protection first (using the original PDF application, Adobe Acrobat, or a trusted removal tool) before merging here.

Use the ↑ / ↓ arrow buttons next to each file to change its position in the merge order. The files are merged from top to bottom in the order shown. You can also drag and drop the rows to reorder them on desktop.

Yes — completely. All processing happens inside your browser using the open-source pdf-lib library. Your PDF files are never uploaded to any server. You can verify this by disconnecting from the internet and using the tool — it works fully offline once the page has loaded.