How to Merge PDF Files and Images Into One PDF

By the Datatool360 team · 14 November 2026

Most online forms want one file, not five. Maybe it is a job application with your certificates, an invoice with its receipts, or lecture notes that were scanned in three goes. Here is how to put them together in a few minutes, in the order you want, without installing anything.

Want to do it right now? Open the Merge PDF tool

When merging is worth it

One file is easier to attach, easier to print and much harder to lose. It also keeps things in the right order: the person who opens it does not have to guess whether “scan2” comes before “scan10”.

Typical cases: an application form plus ID proofs, a visa or loan file, a contract with its annexes, a bill with the proof of payment, or a set of photos of handwritten notes that you want as one PDF. Photos work too, because the tool accepts images as well as PDFs.

Merge PDFs step by step

Open the Merge PDF tool and add your files. You can select several at once, or drag them in. PDFs, PNG, JPEG, WebP and similar images can be mixed. Each image becomes one page.
Drag the files up or down until they are in the order you want. This is the point where most mistakes happen, so look at the list once more before you go on.
If you only need part of a file, type a range into its Pages box. “1-3, 5” means the first three pages and page five. “8-” means page eight to the end. An empty box means all pages.
Press Merge PDFs. The new file is saved to your computer.

All of this happens inside your browser. Your files are not sent to a server, which matters when they contain IDs or bank details.

When the order is not “file by file”

Sometimes you need page 2 of one file between the pages of another. Switch to Page Mode and you will see a small picture of every page. Drag a page to a new place, also from one file into another, or remove a page with the cross in its corner. The merged PDF follows exactly the order you see on screen.

A tip: do the large moves in the file list first and use Page Mode only for the small corrections. It is much quicker than moving thirty pages one by one.

Page labels and duplicate fonts

Some PDFs show page labels that are not the plain page number, for example i, ii, iii for a preface and then 1, 2, 3 for the main text. By default the merged file simply counts 1, 2, 3 from the first page to the last. If you tick “Keep original page labels”, every page keeps the label it had in its own file. Two files can use the same labels, so the result may then contain duplicates. Use this only if the labels matter, for example for a book.

There is also “Remove duplicate fonts”. When you merge many pages from the same source, the same font file can end up in the result again and again. Keeping identical font files once can make the merged PDF noticeably smaller, and the pages look the same.

What goes wrong, and what to do

A file is password protected. It cannot be merged as it is. Unlock it first with the Lock & Unlock PDF tool (you need to know the password), then merge the unlocked copy.
The bookmarks of the original files are not carried over, and fillable form fields may stop working in the merged file. The pages themselves look the same. If you need a working form, keep it as a separate file.
Pages that were rotated stay rotated. If one page is the wrong way round, fix it before you merge.
The merge fails or the browser tab becomes slow. The work is done on your own device, so a lot of big files need a lot of memory. Merge in two rounds instead: first a few files, then the result together with the rest.
The merged file is too big to send. Run it through Compress PDF afterwards.

Before you send it

Open the merged file once and scroll through it. It takes thirty seconds and catches the usual problems: a page in the wrong place, a photo that is upside down, a missing page. Keep the original files until you know that the merged file was accepted.