PureTools
Merge PDF Files, Free & Private
Combine multiple PDF files into one. Drag to reorder, check page counts, merge in seconds, entirely in your browser. No upload, no watermark.
Drop PDF files here
or · up to 100 MB per file
Merging…
How to use the PDF Merger
The PDF Merger lets you combine any number of PDF files into a single document directly in your browser. No account, no upload and no watermark, your files never leave your device. It works on desktop and mobile, and continues to function offline once the page has loaded.
- Add your PDFs, drag and drop files onto the zone, or click Browse to select them from your device. You can add files from multiple folders in separate batches.
- Check page counts, each file card shows its page count and file size as soon as it loads. A running total appears at the top of the list.
- Reorder if needed, drag the handle icon () on any row to move that file up or down. Pages are merged in the top-to-bottom order shown.
- Name your output, edit the filename field to set a custom name for the merged file. The
.pdfextension is added automatically. - Click Merge PDFs, the operation runs in the background so your browser stays usable throughout. A progress bar shows the real completion percentage.
- Download, click the download button to save the merged file. No watermark is added. The merged PDF is built in memory and discarded when you close the tab.
How PDF merging works
This tool uses pdf-lib, an open-source library that reads and writes PDF files entirely within your browser. When you click Merge, each PDF is processed in the background so the page never freezes. Pages are copied from each source document and assembled into a new PDF. Fonts, images, graphics and annotations are transferred exactly as they appear in the originals. The final file is made available to download and the temporary data is cleared from memory.
Privacy and data handling
No file data is ever sent anywhere. The merge runs entirely within your browser tab. PureTools has no server and no way to receive your files. Your output filename preference is saved only for the current session and erased automatically when you close the tab.
Frequently asked questions
Are my PDF files uploaded to a server?
No. Every PDF you add stays entirely on your device. The merge operation runs inside your browser using a JavaScript library called pdf-lib. No file data is ever sent to PureTools servers or any third party. You can disconnect from the internet after the page loads and the tool will still work perfectly. Your data is never used to train AI models or improve machine learning systems.
How many PDF files can I merge at once?
There is no hard cap on the number of files. You can merge 2, 10 or 30 PDFs in a single operation. Each individual file must be under 100 MB and your browser must have enough RAM to hold all files simultaneously. If you notice slowdowns on large batches, split the merge into two smaller operations and merge the results together.
Is there a file size limit per PDF?
Each individual PDF file must be 100 MB or smaller. This limit exists to protect your device memory and keep processing fast. There is no limit on the number of files or the combined page count. Most office documents, scanned reports and presentation exports fall well under this threshold. If you need to merge a larger file, try splitting it first with a PDF splitter.
Does merging reduce the quality of my PDFs?
No. The tool copies pages exactly as they are, fonts, images, graphics, annotations and embedded content are all preserved. There is absolutely no quality loss of any kind. No watermark is added to the output file. Because pages are copied into a new document instead of rasterized, text usually stays searchable and vector graphics remain sharp in the merged output.
Can I reorder the files before merging?
Yes. After adding your files, drag the handle icon on the left of any file row to move it up or down the list. Pages are merged in the top-to-bottom order shown, rearranging rows gives you full control over the final page sequence before you click Merge. You can also remove individual files by clicking the × button on their row.
Why is my merged PDF larger than the sum of the individual files?
PDF files can contain duplicate internal resources, for example, two documents using the same font each carry their own copy. When merged in the browser, those duplicate copies are kept as-is rather than combined, which can make the result slightly larger than expected. This is normal for browser-based tools. To reduce the output size, run the merged file through the PDF Compressor after merging, or compress your images first with the Image Compressor before embedding them in your PDFs.
Does the tool work offline?
Yes, after you have visited the page at least once. PureTools saves the tool locally on your device so it can be used later without an internet connection. On all subsequent visits, even offline, the page loads instantly and the merge runs entirely on your device. For the most reliable offline use, open the merger once while online, then keep the browser cache intact before using it without a connection.
Is my data erased when I close the tab?
Yes. PureTools stores only your preferred output filename for the current session, which is cleared automatically when you close or refresh the tab. Your PDF files exist only in your browser's memory for the duration of your session and are never saved to your disk by this tool. Closing the tab clears everything instantly.