Merge PDFs without Adobe Acrobat, free on Windows and Mac

The short answer

• On a Mac, Preview, the app that opens PDFs and pictures, can join PDFs for free. So can Finder's Create PDF quick action. Both are built in.
• On Windows, nothing built in merges PDFs. Edge opens them and Microsoft Print to PDF makes them, but neither joins two PDFs into one.
• On any computer (Windows, Mac, Linux or a Chromebook), a browser-based merger like Merge PDF does it with nothing to install. Ours builds the new file inside your browser, so your files are never uploaded.

Which one is right depends on your files. For two plain PDFs on a Mac, Preview is quick. When you have many files, fillable forms, bookmarks you want to keep, or a Windows computer you aren't allowed to install software on, the browser route is the easier one. The sections below give the steps for each, and the trade-offs in plain terms.

Why Acrobat Reader won't merge your files

Adobe makes two products with similar names. Acrobat Reader is the free one: it opens, reads, prints and fills in PDFs. Combining files has long been a feature of the paid Acrobat, so in Reader the option is missing or asks you to upgrade. Adobe also offers online tools that work by uploading your file to its servers.

To be fair to Adobe: Acrobat is excellent at what it does. Adobe created the PDF format, and the paid version does far more than merging, such as editing text, recognising text in scans (OCR) and preparing documents for e-signing. If your office already pays for it, use it. But if all you need is to join a cover letter, a resume and some certificates, or a month of invoices, you don't need to buy anything.

On Windows: what's built in, and what isn't

Windows comes with several PDF tools, and it is easy to assume one of them merges. None does:

• Microsoft Edge is the usual PDF reader on Windows. It opens PDFs, lets you highlight and draw on them and prints them. It doesn't combine files.
• Microsoft Print to PDF is a "printer" that saves whatever you print as a PDF file. It is very useful, but it prints one document at a time, so it can't take two PDFs and make one.
• Word can open a PDF, but it converts it into an editable document first. Simple letters come through well; certificates, forms, tables and scans often come out shifted or as pictures. It's a poor way to merge papers that must look exactly like the originals.

One built-in trick is worth knowing for photos, not PDFs. Select several pictures in File Explorer, print them, and choose Microsoft Print to PDF as the printer: you get one PDF with a picture on each page. The print layout may crop or scale the pictures, though. JPG to PDF puts photos into a PDF at full quality, uncropped, and you can merge that PDF with others afterwards.

So on Windows, your free choices are a desktop program you download, an upload-based website, or a merger that runs in the browser. The trade-offs below compare them.

On a Mac: Preview and Finder can do it

macOS has two built-in ways, and both work offline:

• Preview. Open the first PDF and show the page thumbnails in the sidebar. Drag the other PDFs from Finder onto the sidebar, to the place where their pages should go, then save. You can drag single thumbnails to reorder pages too.
• Finder's Create PDF. Select several PDFs or pictures in Finder, then use the Create PDF quick action from the right-click menu. It makes one new PDF next to them.

What they do well: they're already there, free, fast for a few files, and private, since everything stays on the Mac. A few things to watch:

• Preview edits the file you opened. Make a copy of your first PDF before you start, or save the result under a new name, so your original stays as it was.
• Check the order. Create PDF has no screen for arranging files first, so look through the new file.
• No bookmark choices. Neither gives you a setting for bookmarks. If your files have bookmarks or fillable fields, check them in the result.

If you'd like to see each file as a card, drag cards into order and choose how bookmarks come out, Merge PDF runs in any up-to-date browser on a Mac as well.

Merging in the browser, with computer shortcuts

The tool page has the full walkthrough. These are the computer-specific shortcuts that make it quicker:

• Pick many files at once. In the Choose PDF files window, hold Ctrl (Cmd on a Mac) and click each file, or click the first and Shift-click the last to take a whole run.
• Drag and drop. Select the PDFs in File Explorer or Finder and drop them anywhere on the page.
• Copy and paste. Copy PDF files in your file manager and paste them on the page.
• Reorder with the mouse by dragging a card from anywhere. With the keyboard, press Tab until a card's handle is selected, then use the arrow keys; Home and End send it to the start or end.
• Start in the right order. Number your files (1-cover-letter.pdf, 2-resume.pdf) and select them all together. They often arrive already sorted.

After you press Merge and Download, the file goes to your Downloads folder, unless your browser is set to ask where to save each file. In Chrome and Edge on Windows, Ctrl+J opens the list of downloads. The new file is named after your first file, like report-merged.pdf, and your own files are not changed.

The tool doesn't need a fast computer for everyday files. In our tests in Chromium 141, the browser Chrome is built on, a 117-page textbook and a 14-page paper merged into 131 pages in 0.9 seconds, and 20 single-page PDFs into one in 0.6 seconds. Your computer may be faster or slower.

Desktop app, upload site or browser: the honest trade-offs

There are three kinds of free tool outside what's built in. Each has real strengths:

A simple way to choose:

• You merge PDFs every day, offline, and can install software: a desktop program you trust is a good home.
• You need text editing or OCR: that takes a full PDF editor, desktop or online. Merging alone doesn't.
• The files are private, or the computer isn't yours: use a tool that keeps the files on the computer. On a shared computer, delete the merged file from Downloads when you're done.
• The files are big and your internet is slow: skip the upload. A 400 MB scan takes a long time to send to a server and back.

NoUploadPDF also has tools for the jobs that usually come next: Split PDF to take pages out, Organize PDF to move or delete single pages, and the compressor to make the merged file smaller. They work the same private way.

Privacy: what "upload" means, and how to check

When a website uploads your PDF, a copy of the file sits on a computer you know nothing about, at least for a while. Many such sites are well run and promise to delete files after a set time. That may be fine for a menu. For ID cards, salary slips, bank statements, contracts or medical reports, it's a promise you have to take on trust.

An in-browser merger works differently. The page loads its engine (ours is written in Rust and runs as WebAssembly, the way browsers run fast programs safely), then your browser reads your files from your disk and builds the new PDF on your computer. A file that is never uploaded needs no promise to delete it.

You don't have to take our word for it either:

1. Open Merge PDF in Chrome or Edge and press F12 to open the developer tools.
2. Choose the Network tab.
3. Merge two PDFs and download the result.

You will see the page load its own files, and nothing of your PDFs sent anywhere. The page also has a security rule, a Content Security Policy, that tells your browser to block it from sending data to other sites, so it couldn't upload a file even by mistake. Our privacy policy has the details.

Forms, bookmarks and signed files: what to watch when merging

Any tool can put pages one after another. The differences show up in the parts of a PDF you don't see at first glance.

Fillable forms

Say you merge two copies of the same form, one filled for you and one for your spouse. Both have a field called Name. In PDF forms, fields with the same name share one value, so in a careless merge, typing in one copy can change the other. Our merger renames the later field, like Name to Name_2, so each copy keeps its own answers. In our test, two copies of an 8-field form merged with all 16 fields still fillable, the second copy's Last Name renamed Last Name_2. XFA forms, an older kind of form, are left out.

Bookmarks

Bookmarks are the clickable contents list in a PDF reader's side panel. You choose what the merged file gets: one bookmark per file, named after it, with each file's own bookmarks inside (the default); the files' own bookmarks one after another; or none. The guide explains the three bookmark choices with an example.

Digitally signed files

A digital signature proves a file hasn't changed since it was signed. A merged file is a new, changed file, so the signature no longer holds for it, whichever tool you use. Our result tells you when a file had one. The pages look the same, but if someone must verify the signature, send them the signed original as well.

Locked files and the rest

• A password to open: unlock the file first, then add the unlocked copy. The guide's part on locked and signed PDFs shows a free way in Chrome.
• Editing restrictions only: the file can be merged, and the merged PDF opens without those restrictions.
• Tags for screen readers and page labels (custom numbers like i, ii, iii) are left out when several files are merged. If you need a tagged, accessible PDF, combine the parts in the program that made them.
• Title and author come from the first file, so some readers show the first file's title at the top.

Big files and many files

A computer is the best place for big merges, since it usually has more memory than a phone. We set no limit on file size or the number of files; your computer's memory is the only one.

Our largest merge test joined a 400-page colour scan of 455 MB with a 4-page scan. It took 6.6 seconds and made a 404-page PDF of 464.7 MB. While it worked, the browser used about 1.9 GB more memory than when idle, roughly four times the size of the files, because the files and the new PDF are all held in memory at once. Each merge runs in a fresh background worker that closes when it is done, which hands the memory back straight away.

Two things to know about the result:

• It isn't smaller than the parts. Pages are copied exactly as they are, so text stays sharp and scans keep every pixel. Three scans of 23.1 MB in total made a merged file of 23.1 MB. To make it smaller, put it through the compressor, or Resize PDF for an exact limit like 2 MB.
• Mixed page sizes stay mixed. An A4 page stays A4 next to a Letter page. When printing, choose Fit to page in the print window, or make every page A4 with Resize PDF first.

If the browser says the files are too big for its memory, close other tabs and merge in two rounds: half the files first, then that result with the rest. For merging on a phone instead, see how to merge PDFs on iPhone and Android.