How to Combine PDFs in Preview on Mac

Updated 14 November 2026 · Standard formula, shown below

Preview, the built-in PDF viewer on macOS, can merge multiple PDF files into a single document without any extra software. You drag thumbnail pages between windows or use the sidebar to reorder them. This guide shows you both methods, plus how to save the combined file.

What You’ll Need

A Mac running macOS (any recent version works).
The PDF files you want to combine, saved somewhere accessible like the Desktop or Downloads folder.
Preview app (it’s already installed on your Mac).

Step-by-Step

Open the first PDF in Preview. Double-click the file, or right-click and choose Open With > Preview.
Show the sidebar (thumbnails). Click the Sidebar button in the toolbar (it looks like a rectangle with a line down the middle), or press Command-2. You’ll see a column of page thumbnails on the left.
Open the second PDF in a separate Preview window. Double-click the second PDF file. It will open in a new window (if it opens in the same window, press Command-N to create a new window, then drag the file into it).
Show the sidebar in the second window too. Press Command-2 or click the Sidebar button in that window.
Drag pages from the second PDF into the first. In the second window’s sidebar, click a thumbnail to select it. To select multiple pages, hold Command and click each one, or hold Shift to select a range. Drag the selected thumbnails into the first window’s sidebar. Drop them where you want them to appear (above or below an existing thumbnail). A blue line will indicate the insertion point.
Repeat for additional PDFs. Open each additional PDF in its own window and drag its pages into the main window the same way.
Reorder pages if needed. In the main window’s sidebar, drag any thumbnail up or down to change its position. Release when the blue line is where you want the page to go.
Delete unwanted pages. Select a thumbnail and press Delete to remove that page from the combined document.
Save the combined PDF. Go to File > Save (Command-S). If you want to keep the original files unchanged, choose File > Export as PDF… instead, and give the new file a name.

Common Mistakes

Dragging into the document area instead of the sidebar. If you drop a thumbnail onto the main page view, it may not insert correctly. Always drop into the sidebar list.
Opening both PDFs in the same window. Preview can show multiple PDFs as separate tabs. To combine, you need two separate windows. If you see tabs, drag one tab out to make a new window.
Forgetting to save. After combining, if you close the window without saving, all your work is lost. Save immediately after finishing.
Accidentally moving pages within the same document. When you drag a page, make sure you’re grabbing it from the second window, not reordering pages in the first.

Tips

Use the sidebar’s search field. If you have a long PDF, type a keyword to find a specific page before dragging it.
Combine in one step with a drag to the Dock. You can also drag a PDF file icon onto the Preview icon in the Dock, but that just opens it – it doesn’t merge. For merging, use the sidebar method.
Create a new PDF from selected pages. In the sidebar, select pages and drag them to the Desktop – this creates a new PDF containing only those pages. Useful for splitting, not combining.
Keyboard shortcut for saving: Press Command-S after combining to save quickly.
Check page order before saving. Scroll through the thumbnails quickly to make sure everything is in the right order.

Troubleshooting

Pages won’t drag. Make sure you’re clicking directly on the thumbnail, not the page number or the space around it. Also, ensure the sidebar is visible in both windows.
Preview opens both PDFs in the same window. Go to View > Show Tab Bar (if hidden). Then drag one tab out of the window to create a separate window. Or, before opening the second file, press Command-N to create a blank new window, then drag the file into it.
The combined file is too large. Use File > Export as PDF… and choose a lower Quartz Filter (like “Reduce File Size”) to compress it.
Pages appear in the wrong order after dragging. Simply drag them again to the correct position. The blue line shows exactly where each page will land.
Preview crashes or freezes. Close all PDFs, then reopen the main file. If it persists, restart your Mac and try again with fewer files at once.

Frequently Asked Questions

Can I combine PDFs without opening them all in Preview?

Yes. In the Finder, select all the PDFs you want to combine, right-click, and choose Open With > Preview. Preview will open them all in a single window with tabs. Then drag the tabs out to make separate windows and follow the steps above.

Does Preview let me combine PDFs on iPhone or iPad?

No, Preview is only available on macOS. On iOS, you can use the Files app to merge PDFs: select the files, tap the share button, and choose “Print” then pinch out on the preview to create a combined PDF.

Can I combine more than two PDFs at once?

Yes, you can combine as many as you like. Open each in its own window and drag pages into the main window one by one, or open them all in tabs and then drag them out.

Will the original PDFs be changed?

No, unless you save over them. If you use File > Save, the file you have open (the one you dragged pages into) will be overwritten. To keep the original, use Export as PDF… and save with a new name.

Can I combine PDFs with different page sizes?

Yes, Preview will keep each page’s original size. The combined PDF will have pages of mixed sizes, which is fine for most uses.

How do I combine PDFs if I only see a single page, not thumbnails?

Make sure the sidebar is visible. Press Command-2 or click the Sidebar icon in the toolbar. If you still don’t see thumbnails, check that you’re in “Contact Sheet” view (the icon that looks like a grid) rather than “Table of Contents” view.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.