How to merge PDF files: a step-by-step guide

Drop the files anywhere on the page - you don't have to aim at the box - or press Add files and pick them. You can add more at any time, in as many rounds as you like; each joins the end of the list.

Besides PDFs, the tool takes images (JPG, PNG, WebP, GIF, BMP, AVIF) and Word, Excel and PowerPoint files (.docx, .xlsx, .pptx). Each is converted to PDF in your browser as it arrives:

• an image goes on an A4 page of its own, turned to suit it, with a small margin - a phone photo doesn't become a giant odd-sized sheet;
• an Office file is laid out by our own converter. A font the document uses but your device lacks is replaced with a similar one, and charts are left out. When something couldn't be carried over, an amber ⚠ appears on the file's row - hover it to see what.

The icon on each row says what you added: a PDF, a picture, or a Word, Excel or PowerPoint document. The × at the end of a row removes that file; Delete all empties the list.

The merged PDF follows the list from top to bottom. Drag a row by its card to move it - the others slide out of the way while you drag, so you see where it will land.

The sort buttons above the list put the files in order for you: A–Z by name, Pages by page count, Size by file size. Press a button again to reverse the order, and a third time to go back to the order you added them in.

Sorting by name is the quick way to get numbered files - "01 Cover", "02 Contract", "03 Annex" - into the right order.

The middle panel shows the merged document as it will come out: every page in order, each file's pages edged in its own colour, with the page number of the merged PDF under each tile. The header counts the pages of the result, contents and separator pages included.

• A click on a tile selects its file in the list; a file picked in the list is scrolled to in the result.
• By file switches to one file's own pages; Result brings the merged view back.
• Sample pages shows plain placeholders instead of rendering every page - much faster when you only need to see the order of a long stack.

The magnifier in a tile's corner opens the page full size. From there you can page through the whole merged result, across file boundaries: type a page number into the field at the top and press Enter, use the arrows, or swipe sideways on a phone. The caption under the page names the file it comes from.

Separator page in the Options rail puts a page between the merged files, so a printed stack is easy to split by hand:

• Blank page - an empty page between two files (not before the first one).
• Filename - a page with the file's name in front of every file, the first one included, like a divider tab.

A separator page takes the size of the page next to it, so it never sticks out of the stack. A very long file name is shrunk to fit.

Two options make a long merged document easy to find your way in:

• Table of contents page puts a page at the front listing every file with the page it starts on.
• Bookmarks from filename adds one bookmark per file, named after it - the list a PDF reader shows in its side panel, a click on which jumps to that file's first page.

The original files' own bookmarks don't carry over - merging builds a new document. If you need to navigate by file, switch on Bookmarks from filename.

A scanner that only scans one side gives you two files: the front pages and the back pages. Alternate mix interleaves them page by page - file 1 page 1, file 2 page 1, file 1 page 2, file 2 page 2… - into the right reading order.

If the backs were scanned from the last page to the first, reverse that file first with Reverse Pages. Alternate mix works on its own terms, so separator pages, the contents page and bookmarks are switched off while it is on.

Some PDFs number their pages in their own way - i, ii, iii for a preface, then 1, 2, 3 - and a PDF reader shows that in its page box. By default the merged file is numbered 1 to N. Switch on Keep original page labels to carry each file's own numbering over instead. Two files that both start at 1 will then both have a page 1.

These labels are a property of the file, not something printed on the page. To print numbers on the pages, run the result through Page Numbers.

Press Merge PDFs at the bottom of the rail. The line under the button says what will come out ("4 files · 11 pages → 1 PDF"). When the merge is done, the file is saved to your device at once and the button says Saved; a few seconds later it turns into Save, which saves the same file again - handy if your browser held the first download back.

Changing anything - a file, the order, an option - turns the button back into Merge PDFs, so what you save always matches what you see.

A file that needs a password to open appears in the list in red with a lock. Click it, type the password, and from then on it merges like any other. Until then it stays out of the merge, and the line under the button says so.

Without an account, and with a free one, you can merge two files in a run, each up to 15 MB. With Pro there is no limit on the number or the size of the files, and you can save your favourite option combinations as presets (the Presets button at the top of the rail). The work is done on your own computer either way.

• The merged file is too big to e-mail? Compress PDF makes it smaller.
• A page is in the wrong place or not needed? Reorder Pages and Delete Pages.
• Need to cut it into parts again? Split PDF.
• Want page numbers printed on it? Page Numbers.