Merging is the most common thing people do to a PDF after reading it: combining a signed contract with its annexes, assembling scanned receipts for an expense claim, or turning a set of photographed pages into one document to email.
Merging PDFs Step by Step
The order you add files in is the order they appear, so add them in reading order and save yourself the rearranging:
- 1. Open the PDF Merger and add every file you want to combine.
- 2. Drag the file cards to change their order, or drag individual page thumbnails for finer control.
- 3. Rotate any page that came in sideways, and delete pages you do not want.
- 4. To take only some pages, type a range such as 1-3, 5, 8-10 in the page range box. There is one box for the whole merge, and on the Files tab it applies to each file's own page numbers.
- 5. Merge and download the single combined PDF.
If the documents are long, set page ranges rather than merging everything and deleting afterwards. It is fewer steps and the result is easier to check.
Why Merged PDFs Sometimes Look Stretched
A merged file that comes out with stretched text or cropped margins is almost always a page-size problem. Documents from different sources are frequently different shapes — A4 is the standard nearly everywhere, US Letter is shorter and slightly wider, and scans and engineering drawings can be anything.
A merger that forces every page onto one size has to scale or crop to make them fit. The correct behaviour is to keep each page at its own dimensions inside the combined file, so an A4 page stays A4 and a Letter page stays Letter. The result is a document with mixed page sizes, which is completely valid and prints correctly.
Turning Photos into a Single PDF
You do not need a PDF to start with. Add only images and each one becomes a page — which is how most people turn a stack of photographed documents, receipts or ID pages into something they can actually send.
Because a phone photo has no natural page size, there are a few choices worth knowing about:
- Page size: A4 or US Letter for anything that will be printed or filed. Match the document when the photos are joining an existing PDF. The image's own size only if you specifically want the page to be exactly as large as the photo.
- Orientation: following each image handles a mix of portrait and landscape shots without rotating any of them.
- Margin: a small 6 mm or 13 mm margin looks better in print and stops content being lost in a binding.
JPG, JPEG, PNG, WebP and BMP are all accepted. If your photos came off an iPhone as .heic, convert them to JPG first — that format is not accepted directly here.
What to Do After Merging
Merged files get large quickly, particularly when the pages came from photos, and most email systems still refuse attachments over about 25 MB. Compress the result if you are sending it.
If the combined document contains anything confidential, add a password before sharing it rather than after — and if it needs signing, sign the merged file so the signature covers the whole document rather than one part of it.
Summary
Merging PDFs is straightforward as long as two things are handled: the order, which is easiest to get right by adding files in reading order, and page size, which should be preserved per page rather than forced to one shape. The same tool converts photos to PDF with no PDF needed as input, where the choices that matter are page size, orientation and margin. Compress the result before emailing it, and add a password before sharing rather than after.