How to combine PDF files into one document

Before you merge: three things that save a second attempt

Merging is easy. Merging in the wrong order, or finding out afterwards that one file was a Word document and not a PDF, is what costs time. Three checks first.

Make sure every file really is a PDF. A merger only joins PDFs, so .docx, .jpg or .png files have to be converted first (more on that below). Next, decide the order and name the files accordingly: 01-cover.pdf, 02-contract.pdf, 03-exhibits.pdf. Most tools sort by name when you add several files at once, so good names save dragging. Finally, check whether any file is password protected. A locked PDF cannot be merged until you open it with the password and save a copy without it.

Combine PDF files online with Merge PDF

For most people the fastest way is a browser tool, because it works the same on a work laptop, a Chromebook, a Mac or a phone. Merge PDF joins several PDFs into one in the order you choose. It is free, needs no account and adds no watermark. It takes up to 50 files per batch and files up to 300 MB, which covers a year of statements or a full set of exhibits in one go.

The files are processed in memory on DocGopher's own servers and deleted after 30 minutes, which matters when the documents are contracts, medical records or tax forms.

1. Open Merge PDF and drop all the PDFs in at once, or tap to pick them from your phone.
2. Drag the files into the order you want. The first in the list becomes page 1.
3. Click Merge and wait a moment. The result is one PDF with every page of every file.
4. Open the download and scroll through it once to confirm the order before you send it.

Merge PDFs with Preview on a Mac

Every Mac can combine PDFs without extra software. Preview does it through the thumbnail sidebar, and the trick most people miss is where to drop the second file.

One warning: use File, Export as PDF, or just close the window and let Preview save the combined file into the first document. If you press Cmd+S, Preview silently overwrites the first PDF with the merged version. That is fine if you intended it; it is not fine if the first file was the only copy of a signed contract.

1. Open the first PDF in Preview. Choose View, then Thumbnails, so the page sidebar appears on the left.
2. Drag the second PDF from Finder into the sidebar. Drop it below the last thumbnail, not on top of a page. A blue line shows where the pages will land.
3. Repeat for every file. Drag thumbnails up or down to fix the order, or select a page and press Delete to remove it.
4. Choose File, then Export as PDF, and give the merged file a new name.

How do I combine PDF files on Windows without Acrobat?

Windows 10 and 11 can open PDFs in Edge and print to PDF, but neither Edge nor the built-in Print to PDF driver can join two files. Adobe Acrobat Reader, the free one, cannot either; combining files is a feature of the paid Acrobat. So the honest answer is that Windows has no built-in merger.

You have three practical options. The first is an online tool such as Merge PDF above, which needs nothing installed and works inside Edge or Chrome. The second is Word: it can open a PDF, convert it to an editable document, and you can paste the content of another file into it before saving as PDF again, but the layout usually shifts and scanned pages come through as pictures, so this is a last resort. The third is free desktop software such as PDFsam Basic or LibreOffice Draw, which is worth installing if you merge files every week and prefer to keep everything offline.

If you work with confidential files on a locked-down corporate PC, ask IT what is approved before uploading anything.

Combine PDFs on an iPhone or iPad

The Files app can merge PDFs on its own, which few people know. It joins the files in the order they are listed, so rename them with a number first if the order matters.

If the files live in Mail or Messages, save them to Files first: long-press the attachment, choose Share, then Save to Files. If one of the items is a photo rather than a PDF, open it in Photos, tap Share, choose Print, and pinch out on the preview to get a PDF you can save to Files.

1. Open the Files app and put all the PDFs in one folder, named 01, 02, 03 and so on.
2. Tap the three-dot menu in the top right, tap Select, and tap each PDF in order.
3. Tap the three-dot menu in the bottom right and choose Create PDF.
4. A new PDF named after the first file appears in the same folder. Rename it, then share it from there.

Merging Word documents and images with PDFs

A merger only accepts PDFs, so anything else needs converting first. Word has it built in: open the document, choose File, Save As (or Export on Windows), and pick PDF. Google Docs does the same under File, Download, PDF Document. If you have a stack of .docx files and no Word installed, Word to PDF converts them in the browser, with text, tables and pictures kept in place.

For photos and screenshots, the quickest route is Image to PDF, which turns JPG, PNG, HEIC and WEBP files into PDF pages, several images at a time. On a Mac you can also open the images in Preview and print them to PDF; on an iPhone the Print trick described above works for any photo.

Convert everything, name the resulting PDFs in order, then merge them in one pass. Converting first also lets you check each piece: a Word document whose fonts changed, or a photo that came out sideways, is easier to fix on its own than inside a 60-page merged file.

Add page numbers after merging

Each source file carried its own page numbers, so a merged document often reads 1, 2, 3, 1, 2, 1, 2, 3, 4. For a court filing, a thesis or anything printed and stapled, that is a problem. The fix is to stamp a fresh set of numbers over the whole merged file.

Add page numbers does that in the browser: upload the merged PDF, pick a position such as bottom center or bottom right, choose a style, and download. If the old numbers are visible and distracting, place the new ones in a different corner so the two do not sit on top of each other. Do this as the last step, after the order is final, so the numbering never has to be redone.

Keeping the merged file small enough to send

Merging adds sizes together. Five 6 MB scans become a 30 MB PDF, which Gmail refuses and most portals reject. Merging does not compress anything, and if the source files embedded the same fonts, the result can even carry duplicate copies.

Run the merged file through Compress PDF before sending. It shrinks the images inside and removes duplicated data while leaving text sharp; scanned bundles often lose more than three quarters of their size. If one source file is unusually heavy, compress that one first and merge afterwards, so the rest of the document keeps full quality. For a bundle that stays too large even after compression, share a link to it in Drive or OneDrive rather than attaching it.

Fix the page order after merging

If you notice a mistake after the merge, you do not have to start over. Organize pages shows every page of the merged file as a thumbnail, so you can drag pages to a new position, rotate a sideways scan or delete a blank page, then save. It also accepts several PDFs at once, which makes it an alternative to a plain merge when the order inside the files needs changing too.

On a Mac, Preview's thumbnail sidebar does the same for one file: drag a thumbnail to move it, press Delete to remove it, and export when done.