How to Merge PDF Files into One (and Get the Page Order Right)

Combining PDFs is one of the most common paperwork tasks: an application that wants one file for all your documents, a monthly bundle of invoices for the accountant, a report assembled from chapters written by different people. The task is simple, but a couple of details make the difference between a tidy document and one the recipient has to untangle.

When you'll want to merge PDFs

• Upload forms that accept a single file. Many portals have one "supporting documents" box.
• Sending a package. Contract, appendices and signed pages as one attachment is easier for the recipient to file.
• Scans made in batches. Scanners often save each page or each batch as a separate file.
• Reports from several sources. A cover page from one app, tables from another, an appendix that arrived as a PDF.

Ways to merge, compared

Step by step: merge PDFs with MyPDFDone

1. 01Name the files in orderRename the files 01, 02, 03 and so on, so they sort in the order they should appear. It saves dragging later and prevents mistakes.
2. 02Add them to Merge PDFOpen MyPDFDone's Merge PDF tool and add 2 to 20 PDF files, each up to 100 MB.
3. 03Arrange the orderMove files up or down in the list until the order is right. The first file in the list becomes the first pages of the result.
4. 04Check the previewThe merged file and its preview are free. Page through it to confirm nothing is missing, duplicated or in the wrong place.
5. 05Download one PDFDownload the combined file for $2.99, paid once. If it's too big to send, compress it as a final step.

Uploading, merging and previewing cost nothing. You pay only if you download, and it's a one-time $2.99 for that merged file, with no subscription attached. Files are deleted automatically 2 hours after upload.

Getting the order right

Order mistakes are the most common problem with merged files. A few habits help:

1. Number the file names before you start. "01-cover.pdf", "02-contract.pdf", "03-appendix-a.pdf" sort correctly everywhere. Without the leading zero, "10" sorts before "2" in many apps.
2. Merge first, fine-tune afterwards. If one page inside a file is out of place, merge everything, then fix the page order with Organize PDF, where you list the pages in the order you want, for example 1,2,5,3,4.
3. Remove extras at the end. Blank pages, duplicate cover sheets and instructions can be removed in one go with Delete PDF pages.
4. Fix sideways pages. A landscape scan in a portrait document is easy to miss. See how to rotate PDF pages permanently.

Free ways to merge on your device

Mac

Preview can merge PDFs without any extra software. Open the first PDF and show thumbnails (View > Thumbnails). Then drag the second PDF from Finder into the thumbnail sidebar, dropping it where it should go. Repeat for the other files, rearrange the thumbnails if needed, and choose File > Export as PDF to save a new combined file. Exporting a new file, rather than just saving, keeps the original untouched.

iPhone and iPad

In the Files app, tap Select, choose the PDFs (and images, if you like) in the order you want, then tap the More button and choose Create PDF. A new merged file appears in the same folder. The pages follow the order you selected the files in, so select carefully, and check the result before sending.

Windows

Windows has no built-in way to combine existing PDF files. Microsoft Print to PDF prints one document at a time, so it can't join them. You can install a desktop PDF app, or use a browser-based tool. If the content started in Word, a cleaner route is to combine the source documents in Word and export once as PDF.

Android

Android doesn't include a PDF merger either. A browser-based tool works from Chrome or any other mobile browser: add the files from your Downloads or cloud storage, set the order, and download the result.

Merging scans, forms and signed pages

Not every PDF is the same kind of file, and that matters when you combine them.

• Scans merge without any problem, but they're heavy. Expect the merged file to be large and plan to compress it.
• Fillable forms should be filled in and saved before you merge. Interactive fields from several files can conflict when they're combined, and typing into a merged form is less reliable than filling in each original.
• Signed pages keep their visible signature after merging. A certificate-based digital signature, however, covers only the original file: once the pages are copied into a new PDF, that signature no longer validates. If a document has one, send it as a separate file.
• Password-protected files must be unlocked first. See how to remove a password from a PDF.

Size and quality after merging

Merging doesn't shrink anything, so the result is roughly the sum of all the files. Five 4 MB scans make about a 20 MB PDF, which may be too big for email or an upload form. If so, compress the merged file once at the end with Compress PDF, rather than compressing each file separately; one pass also removes duplicated fonts and images that merging can leave behind. Our guide on PDFs that are too large to upload explains which compression level to pick.

Final check before sending

Need to do the opposite and take pages out of a PDF? See how to split a PDF and extract pages.