Merge PDF

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.

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.

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.

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.

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 Amazon Associates recommendations 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.

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.

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.