Why did my merged PDF become larger than the originals added together?

A small size increase is normal — the new file has to carry one combined font table, one metadata header, and one cross-reference index for every page. The increase is usually a few percent. If your output is dramatically larger (for example, 80 MB from three 10 MB sources), one of the inputs probably has uncompressed scanned images. Running it through Compress PDF after merging fixes this without losing readable quality.

Will bookmarks, fillable form fields, and signatures still work after merging?

Bookmarks and hyperlinks are preserved and remain clickable. Fillable form fields keep their input data and stay editable as long as field names don't collide between source files. Digital signatures are a special case: combining a signed PDF with anything else invalidates that signature, because the signature certifies the original bytes — this isn't a tool limitation, it's how PKI signatures work. If you need signatures to remain valid, sign the merged file at the end instead of merging signed files.

Can I merge a scanned PDF from my phone with a PDF I exported from Word?

Yes. The tool doesn't care how each PDF was created. Scanned phone PDFs (which are images inside a PDF wrapper), exported Word files (which are real text), and PDFs from web pages all combine cleanly. The output keeps each page in its native form — text pages stay searchable, scanned pages stay as images. If you want the scanned pages to become searchable too, run OCR on them separately first.

Why is one page rotated or upside down after merging?

Each PDF carries its own page-rotation metadata. If a scanned page was saved with the wrong rotation flag, it shows up tilted in the merged file too — merging doesn't fix or break orientation, it just preserves what was there. Use Rotate PDF on the offending source file before merging, or rotate the page in the combined file afterwards.

Is there a limit on how many files or how large they can be?

There's no hard server limit because nothing uploads — the practical limit is your device's memory. On a typical laptop you can comfortably merge 20–30 PDFs totalling a few hundred megabytes. On a phone you'll start to feel the slowdown around 100 MB total. For very large jobs (a year of statements, hundreds of pages of receipts), it's faster to merge in two passes than to push everything at once.

Are my files uploaded anywhere?

No. Merging runs inside your browser using a JavaScript PDF engine. The files are opened in memory on your machine, recombined locally, and handed back to you as a download. Nothing is sent to F2File, nothing is logged, and there's no server-side copy to delete because no copy is ever created. You can verify this by opening your browser's network tab while merging — you'll see no upload requests.

Can I merge password-protected PDFs?

Not directly. A password-protected PDF has its content encrypted, and the merger can't read encrypted pages. Unlock the file first (with the password you already have) using Unlock PDF, then drop the unlocked version into the merger. If you need the final output protected too, apply a new password with Protect PDF after merging.

Why did my merged PDF become larger than the originals added together?

A small size increase is normal — the new file has to carry one combined font table, one metadata header, and one cross-reference index for every page. The increase is usually a few percent. If your output is dramatically larger (for example, 80 MB from three 10 MB sources), one of the inputs probably has uncompressed scanned images. Running it through Compress PDF after merging fixes this without losing readable quality.

Will bookmarks, fillable form fields, and signatures still work after merging?

Bookmarks and hyperlinks are preserved and remain clickable. Fillable form fields keep their input data and stay editable as long as field names don't collide between source files. Digital signatures are a special case: combining a signed PDF with anything else invalidates that signature, because the signature certifies the original bytes — this isn't a tool limitation, it's how PKI signatures work. If you need signatures to remain valid, sign the merged file at the end instead of merging signed files.

Can I merge a scanned PDF from my phone with a PDF I exported from Word?

Yes. The tool doesn't care how each PDF was created. Scanned phone PDFs (which are images inside a PDF wrapper), exported Word files (which are real text), and PDFs from web pages all combine cleanly. The output keeps each page in its native form — text pages stay searchable, scanned pages stay as images. If you want the scanned pages to become searchable too, run OCR on them separately first.

Why is one page rotated or upside down after merging?

Each PDF carries its own page-rotation metadata. If a scanned page was saved with the wrong rotation flag, it shows up tilted in the merged file too — merging doesn't fix or break orientation, it just preserves what was there. Use Rotate PDF on the offending source file before merging, or rotate the page in the combined file afterwards.

Is there a limit on how many files or how large they can be?

There's no hard server limit because nothing uploads — the practical limit is your device's memory. On a typical laptop you can comfortably merge 20–30 PDFs totalling a few hundred megabytes. On a phone you'll start to feel the slowdown around 100 MB total. For very large jobs (a year of statements, hundreds of pages of receipts), it's faster to merge in two passes than to push everything at once.

Are my files uploaded anywhere?

No. Merging runs inside your browser using a JavaScript PDF engine. The files are opened in memory on your machine, recombined locally, and handed back to you as a download. Nothing is sent to F2File, nothing is logged, and there's no server-side copy to delete because no copy is ever created. You can verify this by opening your browser's network tab while merging — you'll see no upload requests.

Can I merge password-protected PDFs?

Not directly. A password-protected PDF has its content encrypted, and the merger can't read encrypted pages. Unlock the file first (with the password you already have) using Unlock PDF, then drop the unlocked version into the merger. If you need the final output protected too, apply a new password with Protect PDF after merging.

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How it works

Add your PDF files

Drop two or more PDFs onto the page, or click to pick them from your device. Files from your phone, scanner, and computer can all go in together — they don't need to be the same size or page count.

Drag to set the order

The order you drop them in is the order they'll be combined. Drag any file up or down before merging if the sequence matters — for example, putting an ID page first or a signature page last.

Download the combined PDF

Press merge and your single PDF is ready in a few seconds. It downloads directly to your device. Nothing is stored, nothing is queued, and nothing is sent to a server.

Frequently asked questions

About Merge PDF

Most people don't merge PDFs because they want to — they merge because something on the other end requires a single file. A visa application that only accepts one upload. A bank that wants your ID, proof of address, and last three statements as one document. A reimbursement portal that rejects everything except a single combined PDF. This tool combines as many PDFs as you need into one file, in the exact order you choose, without changing the original pages. Bookmarks, fillable form fields, hyperlinks, and digital signatures that were valid on the source files stay intact. Page orientation, embedded fonts, and image quality are preserved — you'll get the same pages back, just stitched together. Everything happens inside your browser. The files never leave your device, which is what you actually want when the documents are bank statements, contracts, or identity papers. There's no upload, no queue, no account, and no copy sitting on a server waiting to be deleted later.

Updated May 2026: rewrote the guide with real document-workflow scenarios (visa, banking, reimbursement) and added FAQ entries on signed PDFs, scanner-export merges, password-protected sources, and unexpected file-size growth.

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