Merge PDF

How to merge PDF files

1. Add your PDFs. Drag them onto the box above, or click to browse. You can select several at once, and add more afterwards.
2. Check the order. Files are combined top to bottom, exactly as listed. Use the up and down arrows to rearrange, or the cross to remove one.
3. Merge. The page count for each file appears as it is read, so you can confirm you have the right documents before combining.
4. Download. The combined PDF is saved straight to your device.

Nothing is uploaded at any point. If you close the tab before downloading, the merged file is gone — there is no copy anywhere else.

When you would need this

Submitting an application as one document. Job applications, visa applications, grant submissions and university forms frequently require a single PDF containing a form, supporting documents and identification. Uploading three separate files when the portal wants one is a common reason for a rejected submission.

Combining scanned pages. Scanners often produce one file per page, or split a long document into batches. Merging turns a folder of fragments back into the document it was meant to be.

Assembling a report from separate contributions. A cover page from one person, a body from another, an appendix exported from a spreadsheet. Merging is faster and more reliable than pasting everything into one editor and re-exporting.

Bundling invoices or receipts. Sending an accountant twelve monthly statements as one file is considerably more useful to them than twelve attachments.

Reassembling a document you split earlier. If you extracted pages to edit or sign them, merging puts the document back together.

Tips for a clean merge

Name your files so they sort correctly. If you select many files at once, they are added in the order your operating system lists them. That order is alphabetical, which means page10.pdf sorts before page2.pdf. Zero-padding the numbers — page02.pdf, page10.pdf — makes the automatic order the right one and saves manual rearranging.

Merge before compressing, not after. Compressing each file first and then merging gives a worse result than merging first and compressing once. Compression works on the whole document, and applying it repeatedly degrades images each time.

Check page counts before you merge. The count next to each file is read from the document itself, so it is a quick way to spot that you have picked up a one-page cover sheet instead of the full report.

Remove passwords first. Encrypted files cannot be read at all. If any of your PDFs is protected, open it in your usual reader, enter the password, and save an unprotected copy before merging.

Merging fillable forms needs care. If your documents contain form fields you intend to keep interactive, merge them, then check the result before relying on it. Field data and interactivity do not always survive being copied between documents. Flattening the forms first — printing to PDF, or using your reader's flatten option — makes them permanent page content that always survives.

Expect mixed results when combining scans with digital documents. A merged file containing both a scanned contract and a digitally generated invoice behaves inconsistently in ways that surprise people. Text search will find words on the digital pages and nothing on the scanned ones, because scanned pages are photographs of text rather than text. File size jumps disproportionately too: a single scanned page can easily outweigh fifty pages of digital text, since it stores a full image rather than a few characters and a font reference.

Neither is a fault in the merge — both are properties the source pages already had, now visible side by side in one document. If you need the whole file searchable, run the scanned pages through text recognition before merging. If size is the problem, compressing after merging targets the images that are actually causing it.

Limits and requirements

Encrypted PDFs cannot be merged. A password-protected document is unreadable without its password, and this tool does not attempt to break encryption. Remove the protection first.

Memory is the real constraint. Every document is held open in memory simultaneously while merging, so the ceiling is your device's available RAM rather than any figure we set. Closing other browser tabs frees a surprising amount. If a merge fails you will get a message explaining why.

Document-level features may not carry across. Page content transfers exactly. Bookmarks, form field interactivity, embedded attachments and cross-page internal links belong to the document structure rather than to individual pages, and are commonly lost. This is a characteristic of how PDF page copying works rather than a shortcoming of this tool.

Digital signatures are invalidated. A cryptographic signature covers a specific document. Merging produces a new document, so any existing signature no longer validates — as it should, since the content has genuinely changed.

Browser support. Any modern browser from roughly the last five years, on desktop or mobile. JavaScript must be enabled.

Privacy: how this tool handles your files

Your PDFs never leave your device. When you add a file, your browser reads it into memory, and the merging is done there by code running in your tab. There is no upload, no server-side processing, no queue and no temporary copy on our infrastructure — because there is no infrastructure involved in the merge at all.

This matters because of what people actually merge. Signed contracts. Bank statements for a mortgage application. Passport and visa scans. Medical records. Payslips. These are precisely the documents you would not hand to an unknown third party, and yet the standard way to merge them online involves doing exactly that.

You can verify the claim rather than trusting it. Open your browser's developer tools, switch to the Network tab, and merge a document. No request carries your file. For a stronger test, load this page, disconnect from the internet entirely, and merge — it still works, because everything needed is already running on your machine.