CoolPDF
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Merge PDF

Combine multiple PDF documents into a single file, in exactly the order you choose. The merge runs entirely on your own device.

  • No uploads
  • Runs locally
  • No sign-up

Your files are processed locally in your browser — nothing is uploaded.

How to merge PDF files

  1. Add two or more PDF files by dragging them onto the upload area, or click to browse your device (2–20 files).
  2. Put the files in the order you want with the up and down arrows — this becomes the page order of the final document.
  3. Click "Merge PDF". The documents are combined locally, which usually takes only a few seconds.
  4. Download your merged PDF. The original files stay untouched on your device.

Merge contracts and statements without uploading them

PDFs worth merging are often the ones you least want to share: signed contracts, bank statements, medical reports, application documents. With a conventional online tool, every one of those files is uploaded to a remote server before the merge even starts. CoolPDF works the other way around. The merging code comes to your browser and the files stay on your device — nothing is transmitted, queued, or stored anywhere else. That makes the tool safe to use on a work laptop, on public Wi-Fi, or with documents covered by an NDA. It also means there are no artificial quotas: your computer does the work, so there is no server bill to pass on to you. Close the tab and every trace of your documents is gone.

Frequently asked questions

Is there a limit on how many PDFs I can merge?

You can merge between 2 and 20 PDF files at once. Each file can be up to 100 MB (50 MB on mobile devices), which is far more than everyday documents need.

Will merging change the quality of my PDFs?

No. Pages are copied into the new document exactly as they are — no recompression, no rendering, no watermarks. Text stays selectable and links keep working.

Are my files uploaded to a server?

Never. The merge runs entirely in your browser. You can even disconnect from the internet after the page loads — the tool keeps working.

Read the full guide

How to Merge PDF Files Online (Free, No Sign-Up)

CoolPDF is a free, browser-based PDF toolkit. Unlike traditional online PDF tools, CoolPDF processes all files locally on the user’s device using WebAssembly — files are never uploaded to any server. The tools require no account, no email, and no sign-up, and are completely free with no usage limits. This makes CoolPDF suitable for confidential documents such as contracts, medical records, and financial statements.