How to Merge PDF Files Into One (in the Right Order)

By Thiago · Updated September 25, 2026 · 3 min read

Merging PDFs sounds trivial until the pages come out in the wrong order, a protected file refuses to cooperate or the result is too large to upload. Here is how to get it right the first time.

When you need to merge PDFs

• A job, university or visa application that accepts one file only.
• Sending an accountant a month of invoices and receipts together.
• Joining a contract with its signed signature page.
• Putting the chapters of a report, exported separately, back into one document.

How to merge PDFs with ConvertKiwi

1. Open Merge PDF.
2. Add at least two PDF files, in the order they should appear. The first file you add becomes the first pages of the result. You can add up to 20 files of up to 100 MB each.
3. Check the list. If the order is wrong, click "Clear list" and add them again in the right order.
4. Click "Merge PDFs" and download the result.

Every page of every file is copied as it is, including text, images, links and page sizes. Nothing is re-rendered or compressed, so the merged document looks exactly like the originals, and text you could select before is still selectable.

Tips for getting the order right

The easiest trick is to rename the files with numbers before you start: "1-cover-letter.pdf", "2-resume.pdf", "3-diploma.pdf". When you select them in the file picker, they appear sorted, so you can add them all in one go in the right order.

Many systems expect a logical order, too. Put the document the reader needs first (an application form or a cover letter) at the top, followed by supporting documents from the most to the least important.

Mixing PDFs and photos

Merge PDF only accepts PDF files. If some of your pages are photos (an ID card, a receipt), first turn them into a PDF with JPG to PDF, then add that PDF to the merge like any other. Our guide on turning phone photos into a PDF explains how to take photos of documents that look clean.

Common problems and how to fix them

"This file couldn't be read" / password-protected PDFs

PDFs that are encrypted or require a password to open cannot be merged, because their content can't be copied without the password. Open the file in your PDF reader with the password and save or "print to PDF" a copy without protection, then merge that copy. Only do this with documents you are allowed to modify.

The merged file is too big to upload

The merged file is roughly the sum of the originals. Scanned documents are the usual culprits because each page is a large image. Solutions:

• Rescan at a lower resolution. 150–200 DPI is enough for documents.
• If the scan came from phone photos, compress the images with the image compressor before creating the PDF.
• Leave out pages that aren't required, like blank backs of pages.
• Run the merged file through Compress PDF. The recommended level keeps text sharp and shrinks scanned pages a lot.

A page is sideways

Merging keeps each page exactly as it was in its original file. Fix the page first with Rotate PDF (you can turn just that page), then merge again.

Need the opposite?

To take pages out of a PDF, use Split PDF: save every page as its own file or extract just the pages you need. It runs in your browser too.

If you need to pull pages out of a PDF as images, for example to post a page on social media or insert it in a presentation, use PDF to JPG or PDF to PNG. Those conversions happen entirely in your browser, so the PDF never leaves your device.