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Merge PDF files

Combine PDFs into one document in seconds. Free, no limits, and your files never leave your device.

or drop files here

Processed on your device – files are never uploaded

Merging PDFs is handy when you need to send several documents as one: a job application with a CV and certificates, monthly invoices, scanned pages or the chapters of a report. With PDF4U you choose the files, put them in the right order and download a single PDF.

Unlike most online PDF mergers, PDF4U doesn’t upload your files. The files are combined inside your browser on your own device, so it’s fast, works with large files and keeps confidential documents private. Page sizes, orientation and links on every page are kept exactly as they are.

You can combine PDFs of any page format: A4 scans, US Letter forms and landscape slides end up in one document, each page exactly as it was. Add files in several rounds, sort them by name with one click, or drag them into place – on a phone, use the handle on each card. Once the merged PDF is ready, continue with Organize PDF to fine-tune the page order, Add page numbers to number the pages, or Compress PDF to make the file small enough for email.

How to merge PDF files

  1. Select your PDFs

    Click “Select PDF files” or drag and drop two or more PDFs onto the page. You can add more files at any time.

  2. Put them in order

    Drag the files into the order you want, or use the arrow buttons. You can also sort them by name.

  3. Merge

    Click “Merge PDF”. By default every file gets a bookmark and its own bookmarks are kept. Your browser combines the files on your device – nothing is uploaded.

  4. Download

    Click “Download” to save the merged PDF. Need a smaller file? Continue with Compress PDF.

Frequently asked questions

Is it safe to merge PDFs with PDF4U?

Yes. Your files are merged by your own browser and are never uploaded to a server, so nobody else can see them. Our pages are also blocked from connecting to other websites, so the files can’t be sent anywhere by mistake.

Can I print the merged PDF double-sided?

Yes. Tick “Add a blank page after files with an odd number of pages”: every file then starts on a front side when you print double-sided. Merging is free, with no sign-up, no watermark and no daily limit.

How many files can I merge at once?

There is no fixed limit. You can merge dozens of files or very large PDFs; the only limit is the memory of your device. On phones, very large files (hundreds of megabytes) may be slower.

Can I merge password-protected PDFs?

Remove the password first with Unlock PDF (you need to know the password), then merge the unlocked files.

Will the merged PDF keep the original quality and bookmarks?

Yes. Pages are copied as they are, without re-compressing text or images. The files’ own bookmarks are kept, nested under one new bookmark per file so you can jump straight to each document – or choose “Keep existing only” or “None”.

Can I merge PDFs on my phone?

Yes. PDF4U works in modern browsers on Android, iPhone, iPad, Windows, Mac and Linux. No app is needed.

Can I combine PDFs and images in one file?

This tool combines PDF files. Turn your photos or scans into a PDF first with JPG to PDF, then merge that PDF with your other files here.