Merge PDF
Combine multiple PDF files into one document in the order you choose, then download the merged file.
Other useful tools
Free tools that often go together. Everything runs in your browser.
How to use this tool
- Add your PDFs by dragging them into the dropzone or clicking Choose files. You can add up to ten documents per merge job.
- Set the merge order by dragging files in the list, or use the up and down buttons. The preview strip at the bottom shows the first page of each file in the order they will appear in the final PDF.
- Click Merge PDFs when you have at least two valid files. Processing runs entirely in your browser and usually finishes within a few seconds.
- Save the merged file when your download starts. Use Clear files when you want to remove everything and start a new job.
Frequently asked questions
What does the merge PDF tool do?
The merge PDF tool combines two or more separate PDF files into a single document. You control the order before processing, so chapter one can stay before chapter two, or invoices can be grouped in the sequence you need. The output is one standard PDF file that opens in any PDF reader. All processing happens on your device. Your files are not uploaded to Justools or any third-party server for merging.
Is my data secure when I merge PDFs here?
Yes. When you use Justools, your PDFs are read from your device and merged locally using JavaScript libraries in the browser. The file bytes do not travel to our servers for processing, storage, or logging. That makes the tool suitable for personal documents, school work, internal business files, and other material you would not want to send to an unknown cloud service. You should still follow your own organisation's rules for highly sensitive data.
What are the file size and count limits?
Each merge job supports between 2 and 10 PDF files. Every individual file can be up to 25 MB, and the combined size of all files in one job cannot exceed 100 MB. These limits keep processing fast and stable in the browser, especially on phones and tablets. If you hit a limit, try merging in smaller batches or compressing large scans before uploading.
Will my files still be here if I refresh the page?
In most cases, yes, within the same browser. Justools stores your selected files in local browser storage (IndexedDB) so an accidental refresh does not force you to pick everything again. Your list and order are restored until you tap Clear files or clear site data for justools.io. This storage never leaves your device. We do not receive a copy of your documents. Private browsing modes may not persist files after you close the tab.
Do I need an account or subscription?
No. Merge PDF is free to use with no login, no email sign-up, and no premium tier for basic merging. Justools is supported by display advertising on the site. There are no watermarks added to your merged PDF and no limit on how many times you can download the result from a completed job.
Why does my merged PDF look different from the originals?
Merging combines the existing pages of each source PDF in order. It does not reformat text, change fonts, or flatten forms unless the source files already use those properties. If one input file is landscape and another is portrait, both are preserved as they were. For best results, use PDFs exported from the same application or scan settings when possible.
Can I use this tool on mobile?
Yes. The merge tool works on modern phones and tablets. Very large files may process more slowly on mobile because the device has less memory than a desktop. If the browser tab closes or crashes during a heavy job, try fewer files at once or switch to a desktop browser for large merges.
Processed locally in your browser. Your files are never uploaded to our servers.