Merge PDF

What this tool does

Merge PDF joins two or more PDF files into one document. Add the files, put them in the order you want, and the tool copies every page into a new PDF entirely on your device. It is useful when an application, client, or colleague needs one attachment instead of a folder full of separate files. Because the merge runs in your browser, the documents are not sent to an All PDF Needs processing server. That can make a practical difference for invoices, contracts, HR paperwork, scans, and other files you would rather not upload to a third-party converter. Merge PDF combines whole files in their current page order. If you need to remove, rotate, or rearrange individual pages before combining them, clean each source first with Reorder PDF Pages, Delete Pages, or Extract Pages.

How to use it

1. Collect the final versions of the PDFs you want to combine. If a source is password-protected, unlock it first only when you know the password and have permission to edit it.
2. Drop or select at least two PDF files. The file list shows the order the pages will follow in the finished document.
3. Use the up and down controls to move each source file until the list matches the order you want. For example, place a cover letter before a résumé, or a cover note before an invoice and its receipts.
4. Check that you have included every document and removed any outdated draft from the list. Merge works with whole source files, so page-level cleanup should happen before this step.
5. Click Merge PDFs. The browser creates a new combined PDF locally and shows a download button when it is ready.
6. Open the downloaded file and review the first, middle, and final pages before you email or submit it. Add page numbers afterward if reviewers will need to reference pages.

Common use cases

• Assemble a job application packet with a cover letter, résumé, references, and portfolio samples in the requested order
• Combine signed contract pages from different scans into one client-ready agreement
• Create a single invoice packet from a cover note, invoice, receipts, and supporting documentation
• Join chapter PDFs or handouts into one reading packet for printing or sharing
• Prepare a board, legal, or project packet after organizing each source document

FAQs

Do my files get uploaded?

No. Merging runs in your browser with @cantoo/pdf-lib (in a Web Worker). Files stay on your device.

Why is Merge disabled?

You need at least two PDFs. Add another file, then Merge becomes available.

Can I change the order of the PDFs before merging?

Yes. Use the up and down controls in the file list. The tool combines files in that displayed order, so review it before you click Merge PDFs.

Is there a file limit?

Free plans soft-warn above 20 MB and hard-cap at 50 MB per file. Very large files may be slower on phones, but still process locally.

Can I reorder pages inside a file?

This tool merges whole files. Use Reorder PDF Pages to rearrange pages inside one file, or Extract Pages / Split PDF, then merge.

Does merging reduce PDF quality?

Merge PDF copies pages into a new document; it does not intentionally downsample pages or images. If you need a smaller attachment after combining files, use Compress PDF on the finished packet.

What should I do after merging?

Open the downloaded file and check page order, then use Add Page Numbers for review packets, Watermark PDF for drafts, or Compress PDF before email when the attachment is large.

What if a PDF is password-protected?

Unlock it first with Unlock PDF (only for documents you own), then merge.