Merge PDF online for free. Combine several pdfs into one document in seconds — fast, secure, and with no software to install.
This free tool lets you merge PDF files in the browser — drop in two or more PDFs and PDF4 combines them into a single document. The output is one continuous PDF, in the order you added the files, with all original pages preserved. No signup, no watermark, no installer.
Files are concatenated in the order you upload them, so the easiest way to control the final result is to add them in the sequence you want. If you need to interleave pages from different documents or insert a specific page mid-way through another, first use Extract PDF Pages to pull the slices you need, then merge those slices here. To go the other way and break a merged file back apart, see Split PDF.
PDF4 preserves page content as-is during a merge. Internal hyperlinks that pointed to pages inside the same source file remain valid because every page is kept. Top-level bookmarks from each source are carried over where possible. Heavy interactive forms can behave unpredictably across documents — if you need a final static deliverable, run the result through Flatten PDF, and use Compress PDF if the combined file is too large to email.
For batch jobs or automations, the same merge is available through the PDF4 API and to AI agents over MCP, so you can combine documents from a script or an agent run.
Yes. You can combine several PDFs into one document right here online for free — no account, email, or credit card required. Sign up only if you want higher limits, larger files, or API access.
Yes. Uploads travel over an encrypted HTTPS connection, are processed on our servers, and are automatically deleted within a few hours. We never share or sell your documents.
No. PDF4 works entirely in your web browser, so there is nothing to download or install. It runs on Windows, macOS, Linux, Android, and iOS.
Yes. Files are merged in the order you add them, so arrange them before processing to control the final page order. To insert pages from one PDF in the middle of another, extract the pages you need first, then merge the slices in the order you want.
You can merge as many files as you like in one go, up to the free per-file size limit. For very large jobs or automation, the merge endpoint in the PDF4 API handles arbitrary batches.