The short answer
Drop two or more PDFs into the merger below, drag them into order (or press Sort by name), then press Merge PDF and download the file. Each file shows its page count, so you can check the total before merging. The pages are copied as they are, without being converted, so text stays selectable and images keep their original quality.
The merged file is named after the first PDF in the list, with merged added to the name. Your original files are not changed.
Try it here: Merge PDF
Open the full tool pageWhat merging actually does
A PDF is a collection of independent pages plus shared resources such as fonts and images. Merging takes the pages of each file in the order you set and writes them into a new document. Nothing is printed again or turned into an image, which is why a merged file looks exactly like its parts.
Because pages are copied rather than rebuilt, the merged file is roughly the size of all the parts added together. Merging three files of 400 KB, 1.2 MB and 300 KB gives a file of about 1.9 MB. If two parts embed the same font, it may be stored twice, so the total can be slightly larger than the sum. If the result is too big for an email or an upload form, compress it after merging, not before.
Built in options on each device
Every major system can merge PDFs in some way, but the free built in tools differ a lot. Here is what you can use without installing anything.
- Windows: there is no built in merge function. Microsoft Print to PDF and the PDF viewer in Edge save one document at a time, and the free Adobe Acrobat Reader cannot combine files (that needs a paid Acrobat plan). A browser based merger like the one above is the simplest free option.
- Mac: open the first PDF in Preview, show the sidebar with View > Thumbnails, then drag the other PDF files into the sidebar where they should go. Save with File > Export as PDF so the original stays untouched.
- iPhone and iPad: in the Files app, tap Select, choose the PDFs, tap the More button and pick Create PDF. The files are merged in the order of the folder view, so rename or sort them first if the order matters.
- Android: there is no system wide merge feature. Open this page in Chrome or another browser, tap the drop area to pick the files from your storage or Google Drive, and download the merged PDF to your Downloads folder.
- Chromebook: use the browser method, as on Android.
Getting the page order right
The order of the files in the list is the order of the pages in the result. Drag a file up or down, or use the arrow buttons on its row. Sort by name sorts numbers naturally, so 2.pdf comes before 10.pdf. Naming files 01 cover, 02 letter, 03 invoice before you add them is a quick way to get a fixed order.
The merger joins whole files. If you only need some pages from a document, or a page is upside down, merge first and then open the result in the Organize PDF tool through the Next step bar: there you can drag single pages, rotate them and delete the ones you do not need.
Mixing scans, photos and documents
Applications often combine a typed letter with a scanned ID, a photo of a receipt or a certificate. The merger accepts PDFs only, so turn photos into PDF first with the Image to PDF tool (it can fit them on A4 or Letter pages and fixes sideways phone photos), then merge everything here.
Scans are usually much heavier than typed pages. A single color page scanned at 300 DPI can weigh 1 to 3 MB, while a page of text from Word is often under 100 KB. If the merged file is too large, run it through Compress PDF: images get smaller while the text of your typed pages stays sharp.
| Part of the package | Typical size per page | Tip before merging |
|---|---|---|
| Text PDF saved from Word or Google Docs | 20 to 100 KB | Nothing to do |
| Grayscale scan at 200 DPI | 100 to 400 KB | Scan in grayscale when color is not needed |
| Color scan at 300 DPI | 1 to 3 MB | Compress the merged file afterwards |
| Phone photo of a document | 2 to 5 MB | Crop to the paper edge, then use Image to PDF |
What may not carry over
The visible content of every page is kept. Some interactive parts of a PDF are tied to the original file and are not part of the page itself, so check these if they matter to you.
- Bookmarks (the outline in the sidebar of a PDF reader) are not carried into the merged file.
- Fillable form fields may lose their function. Fill in and save forms before merging, so the entered text becomes part of the page.
- Links to web addresses usually keep working, but links that jump to another page inside the original document may not.
- Password protected PDFs cannot be merged until the password is removed in your PDF reader.
- Documents with a digital signature lose the signature validation when they are combined with other files, because the signed file has changed. Send signed contracts as separate files if the recipient needs to verify the signature.
Tips for a clean merged PDF
- Check the page count shown for each file before merging, so missing or duplicate pages are easy to spot.
- Put a short cover page or the main document first: many people only read the first page of an attachment.
- Merge everything first and compress the result once. Compressing each part and merging later often ends up larger.
- Add page numbers after merging if the recipient will refer to specific pages.
- Keep the originals until the recipient has confirmed that everything arrived.