How do I combine two PDF files?

Add both PDF files using the file picker or drag and drop, use the arrows to set the order, then click Merge. The combined PDF downloads automatically.

Is it safe to merge PDFs in a browser?

Yes. This tool runs entirely in your browser using the pdf-lib library. All processing happens locally on your device.

Is there a file size limit?

Each PDF can be up to 100 MB. Larger files are rejected with a clear error before any processing starts.

Can I reorder the two PDFs before merging?

Yes. Use the up and down arrow buttons on each file row to set the order before you click Merge.

What happens to the original files?

Nothing, only a new combined PDF is downloaded. Your original files are unchanged on your device.

Combine Two PDF Files

Add two PDF files, arrange them in the order you want, and download the merged result. All processing happens in your browser.

Drop PDF files here or click to browse

You can add multiple files

How it works

Both PDFs are loaded into memory and parsed with pdf-lib. The tool calls copyPages() to clone every page object from the first document, then calls addPage() on a fresh target document to insert them in the order you chose, followed by every page from the second document. The combined PDF is serialised in your browser and downloaded straight to your device.

Processing runs in your browser

All merging happens inside your browser tab. pdf-lib combines your PDFs entirely in memory, with no network requests. You can confirm this yourselfin your browser's DevTools Network tab.

Related operations

For pulling out a single section before merging, try split PDF. To straighten sideways scans first, use rotate PDF. For shrinking the combined file, see compress PDF.

Frequently asked questions

How do I combine two PDF files?: Add both PDF files using the file picker or drag and drop, use the arrows to set the order, then click Merge. The combined PDF downloads automatically.
Is it safe to merge PDFs in a browser?: Yes. This tool runs entirely in your browser using the pdf-lib library. All processing happens locally on your device.
Is there a file size limit?: Each PDF can be up to 100 MB. Larger files are rejected with a clear error before any processing starts.
Can I reorder the two PDFs before merging?: Yes. Use the up and down arrow buttons on each file row to set the order before you click Merge.
What happens to the original files?: Nothing, only a new combined PDF is downloaded. Your original files are unchanged on your device.

Combine Two PDF Files

How it works

Processing runs in your browser

Related operations

Frequently asked questions

Related tools