How to merge PDFs on a phone

Why this is awkward on a phone

Phones are good at opening PDFs and bad at combining them. iOS can merge files in the Files app if you know where to look, and the option moves between iOS versions. Android has no built-in equivalent at all, so the usual answer is to install something.

Most of the apps you find are free to install and then ask for a subscription at the moment you press export. The ones that are genuinely free tend to send your document to a server, which is a strange thing to do with a contract or a payslip when the phone in your hand is perfectly capable of the job.

Four steps

1. Open the merge tool in your phone's browser. Go to pdfsansar.com/merge-pdf in Safari or Chrome. There is nothing to install and no account to make.
2. Add your PDFs. Tap the drop zone and pick the files. On iPhone they will be under Browse in the Files app; on Android, under Downloads or Drive.
3. Put them in the right order. Use the up and down arrows next to each file. The order in the list is the order in the finished document.
4. Merge and save. Tap Merge & download. The combined PDF is built on the phone itself and saved straight to your downloads.

Finding the files in the first place

The file picker is the part people get stuck on, because a PDF you were emailed is not obviously anywhere.

• iPhone: save the attachment first. Open it in Mail, tap the share icon, then Save to Files. It will then appear in the picker under Browse.
• Android: attachments usually land in Downloads already. If the file is in Drive, the picker has a Drive section.
• Either phone: a PDF you scanned with the camera is normally in Photos or Files, depending on the app that made it.

What to expect

A handful of ordinary documents merges in a second or two. Phones have less memory than laptops, so a set of large scanned files can be slow, and a very large batch may not finish at all. If that happens, merge them in two goes and then merge the results.

Everything above happens on the phone. You can put it in airplane mode after the page loads and the merge still works, which is the simplest proof that nothing was uploaded.

If the order comes out wrong

The list is the order, top to bottom. It is worth a glance before you tap merge, because fixing it afterwards means doing it again. If you have already merged and the order is wrong, delete and reorder pages will rearrange the finished file without starting over.