How to Merge PDF Files
Documents arrive in pieces. A contract comes separately from its annexes, a scanner produces one file per batch, a report and its appendices were written by different people. Sending the set as five attachments makes the recipient reassemble it mentally, and gives them five chances to read things in the wrong order.
Merging turns the pieces into a single document with continuous pages in the order you choose. This guide covers doing that in the browser, getting the order right the first time, and what to do about files that refuse to merge.
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Open the toolWhen you need to merge PDFs
- Assembling a contract with its annexes into one file to send for signature.
- Joining scanned batches when the scanner produced a separate file for every few pages.
- Building a single submission — application form, certificates, proof of payment — for a portal that accepts one file.
How to merge PDF files step by step
Open the Merge PDF tool
Go to the Merge PDF page. It works in the browser with nothing to install and no account required.
Add all the documents
Drag the files onto the upload area or select them from the dialog. Add everything before you start ordering — it is easier than inserting a forgotten file later.
Put them in the right order
Drag the thumbnails until the sequence matches the document you want. Upload order is rarely the order you actually need, so this is the step worth slowing down for.
Merge
Start the merge and wait a moment while the pages are combined into one continuous document.
Download and check the seams
Download the result and look at the joins between the original files. That is where a missing or duplicated page shows up, and it is much easier to fix now than after sending.
Common problems and how to fix them
One file will not merge
It is usually either password-protected or slightly corrupted. Remove the password with Unlock PDF, or run the file through Repair PDF, and then merge again.
Pages ended up in the wrong order
No need to start over. Open the merged file in the Organize PDF tool and drag the pages into place there.
The merged file is very large
Sizes add up, and scanned documents add up quickly. Compress PDF usually brings the combined file back within an email limit with no visible loss.
Merge or send separately
Merge when the documents form one logical whole: a contract with annexes, a report with appendices, a scan split across several files. Continuous page numbers make it easier to reference, to sign and to print, and there is only one file to lose.
Keep them separate — or pack them into a ZIP archive — when each document has its own identity and will be filed independently, such as a set of invoices for different months. Merging those makes them harder to work with, not easier.
Questions fréquentes
How many files can I merge at once?
There is no fixed limit on the number of documents. Each file can be up to 100 MB, and there is no daily quota.
Is page quality reduced?
No. Pages are copied into the new document as they are, so nothing is re-encoded or degraded.
Can I merge only certain pages of a file?
Extract the pages you want first with the Split PDF tool, then merge the results.
Why does one of my files fail?
Encrypted and damaged documents cannot be merged directly. Unlock or repair the file first.
Can I change the order after merging?
Yes. The Organize PDF tool lets you rearrange pages in an existing document.
Are my files kept on the server?
No. Everything uploaded is deleted automatically one hour after processing.
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