Guide · 4 min read
How to merge PDF files — a complete guide
Everything you need to combine PDFs the right way: what merging actually does, how to control page order, how to do it on any device, and how to fix the problems people run into most.
What merging a PDF actually does
Merging takes the pages of two or more PDFs and puts them, in the order you choose, into one new PDF. Nothing on the pages is changed: text, images, links inside the page and page sizes all come through untouched.
What does not come along are document-wide extras that belong to each original file rather than to its pages:
- Bookmarks (the outline/sidebar in your PDF reader).
- Fillable form fields — fill and flatten forms first if you need the answers kept.
- Digital signatures — a merged file is a new document, so any certificate-based signature no longer applies to it. Merge first, then sign.
How to merge PDFs with this tool
- Add your files. Click Choose PDF files or drop them onto the page. You can add up to 50 files (about 200 MB in total).
- Put them in order. Drag the cards, or use the ↑ ↓ buttons — handy on a phone or with a keyboard. Sort A→Z orders them by file name in one click.
- Choose pages (optional). Leave the page box empty to include the whole file, or type a range such as
1-3, 5or10-(page 10 to the end). - Merge and download. Click Merge. The new PDF is created on your device and downloads straight away.
Getting the page order exactly right
The page range box is the quickest way to leave out cover sheets, blank pages or duplicate signatures without editing the originals. A few examples:
| You type | You get |
|---|---|
| (empty) | Every page of that file |
2- | Everything except the first page |
1-3, 7 | Pages 1, 2, 3 and 7 |
5 | Only page 5 |
Need to reorder individual pages across files, delete a page in the middle or add a blank page? Merge first, then open the result in Organize PDF Pages, which shows every page as a thumbnail you can drag around.
Merging PDFs on Windows, Mac, iPhone, Android and Linux
This page works the same in any modern browser, on any device. If you'd rather use what's built into your system, here's what's available:
| Device | Built-in option | Notes |
|---|---|---|
| Windows | None | Windows can print to PDF but can't combine PDFs — use this page in Edge or Chrome. |
| Mac | Preview | Open the first PDF, show View → Thumbnails, drag the other PDFs into the sidebar, then File → Export as PDF. |
| iPhone / iPad | Files app | Tap Select, choose the PDFs, tap ⋯ (More) → Create PDF. Order follows the file list. |
| Android | None | Android doesn't include a PDF merger — open this page in Chrome and it works the same as on a computer. |
| Linux | Command line | pdfunite a.pdf b.pdf out.pdf (poppler-utils) or qpdf --empty --pages a.pdf b.pdf -- out.pdf. |
Common problems and how to fix them
| Problem | Why it happens | Fix |
|---|---|---|
| “This PDF is password-protected” | The file's content is encrypted. | Remove the password with PDF Unlock (you need to know it), then merge the unlocked copy. |
| The merged file is too big to email | Merging adds the files together; scans are large. | Use Compress PDF — Balanced keeps text selectable. |
| Some pages are sideways | Scanner or phone saved them rotated. | Fix them in Rotate PDF, before or after merging. |
| Pages are different sizes | A4 and Letter (or photos) mixed together. | That's normal — every page keeps its size and readers show them fine. |
| “Damaged file” or it won't open | The PDF's internal index is broken. | Run it through Repair PDF, then add the repaired copy. |
| Bookmarks or form fields are gone | They belong to the original document, not its pages. | Keep the originals for editing; merge final, flattened versions. |
Is it safe to merge private PDFs here?
Yes — and you don't have to take our word for it. The merging is done by your own browser using open-source PDF code, so your files are never sent to a server: not to us, not to anyone.
That makes it a good fit for contracts, payslips, medical letters, ID scans and anything else you wouldn't want sitting on someone else's computer. When you close the tab, the files are gone from memory.