All tools PDF Merger ● Live PDF Tools How this tool works

PDF Merger

PDF Merger loads multiple PDF files using pdf-lib and combines their pages into a single PDF in the order you specify. Use the up/down buttons to reorder files before merging. The merged PDF is generated entirely in the browser and downloaded directly.

PDF Merger Runs locally

Upload PDF files

Step by step

How to use it

  1. Upload two or more PDF files using the upload area or drag and drop.

  2. Review the file list — each entry shows the file name and page count.

  3. Use the up/down arrows to reorder files into the sequence you want in the final PDF.

  4. Click Merge to combine all files into one document.

  5. Download the merged PDF to your device.

When to use it

Use cases

  • Combine multiple scanned pages into a single PDF for submission.

  • Join separate invoice or receipt PDFs into one file for bookkeeping.

  • Assemble chapters or sections from separate documents into a single report.

  • Merge a cover letter PDF with a resume PDF before applying for a job.

  • Combine signed contract pages that were scanned individually.

Limits & privacy

What this tool does and does not do

Private by design

All merging happens locally in your browser using pdf-lib. Your PDF files are never uploaded to a server.

  • Password-protected or encrypted PDFs must be unlocked before merging.

  • Very large files (hundreds of MB combined) may be slow or use significant browser memory.

  • Merging does not flatten or remove existing bookmarks/annotations from source files.

Background

What survives a merge and what does not

Merging copies pages out of each source document and into a new one. Everything that lives on a page comes with it — text, images, vector art, and page-level annotations.

What does not come with it is anything stored at document level rather than on a page. Bookmarks and outlines are the ones people miss most: a 200-page manual with a full table-of-contents tree arrives merged and bookmark-free. Interactive form fields are the other. An AcroForm is a document-level structure, so merging two fillable PDFs produces a document where the fields' appearance is drawn on the page but the fields themselves no longer function.

If you need the bookmarks or the form, merge is the wrong operation and no browser tool will do better — that requires rebuilding the outline tree and the form dictionary, not copying pages.

Files are opened with encryption ignored, so a PDF carrying owner restrictions — the flags that disable printing or copying — will still open here. That is not password cracking: a document locked with a user password, the kind that demands a password before it renders at all, cannot be opened without it and will simply fail to load.

Questions

Frequently asked questions

Is there a limit on file count or size?

There is no hard limit, but very large PDFs may be slow to process depending on your device's memory, since all files must fit in the browser's available RAM simultaneously.

Does it preserve fonts and images?

Yes. pdf-lib copies pages with their full content including embedded fonts, images, vector graphics, and annotations — nothing is rasterized or re-rendered.

Can I change the order of pages within a single PDF?

This tool reorders whole files in the merge queue. To reorder individual pages within one PDF, use the PDF Splitter to extract pages first, then merge them back in the order you want.

Will merging reduce PDF quality?

No. Merging copies the original page content as-is, so there's no re-encoding, compression, or quality loss.

Are passwords or encryption preserved?

Password-protected PDFs cannot be merged directly — remove the password first using a PDF editor, then upload the unlocked file.

Can I merge PDFs with different page sizes?

Yes. Each page keeps its own original dimensions in the merged document; pages don't need to match in size or orientation.

What's a typical use case for merging PDFs?

Combining scanned documents, joining multiple invoices into one file for accounting, or assembling a report from separate chapter PDFs.