How to uncrop a PDF

Usually, yes. A PDF crop changes the visible area of a page, not the content on it. Adobe states that “cropping a PDF only hides content” and that resetting the page size brings back the full original content (Adobe). Apple’s Preview also crops PDF pages by hiding content (Apple). So the cut-off text and images are normally still in the file, waiting to be shown again.

How PDF cropping works

Every PDF page has a set of boxes that define its size. The crop box is the visible or printable area. Acrobat Pro also lets you set an art box, a trim box and a bleed box, which matter for professional printing (Adobe). Cropping shrinks the crop box and leaves the page content alone. That is also why, as Adobe notes, cropping does not reduce the file size.

Where the PDF was cropped	Can you undo it?	How
Adobe Acrobat	Usually	Crop page, then Set To Zero
Preview on Mac, just now	Yes	Edit > Undo Crop
Preview on Mac, earlier	Sometimes	File > Revert To > Browse All Versions
Received already cropped	Often	Reset the page boxes in Acrobat

Uncrop a PDF in Adobe Acrobat

The steps open the same dialog used for cropping, then reset it (Adobe):

1. Open the PDF in Acrobat and select Edit in the top toolbar.
2. Select Crop page in the left pane.
3. Drag a rectangle anywhere on the page, then double-click inside it. The Set Page Boxes dialog opens.
4. Select Set To Zero to reset all the crop margins.
5. Under Page Range, select All if every page was cropped, or choose the pages you need.
6. Select OK.

To see what is going on, turn on Show All Boxes in the same dialog. Acrobat then outlines each box in color: the crop box in black, the art box in red, the trim box in green and the bleed box in blue. The art, trim and bleed boxes can only be changed in Acrobat Pro.

The same steps are worth trying on a PDF that someone else cropped. If the page grows back to its full size with the missing content, the crop only hid it.

Uncrop a PDF in Preview on Mac

Preview has two ways back, depending on how long ago you cropped (Apple):

• Right after cropping: choose Edit > Undo Crop.
• Later: choose File > Revert To > Browse All Versions, find a version from before the crop and click Restore. To keep the cropped file as well, hold Option and click Restore a Copy (Apple).

macOS saves a version when you open a document and about every hour while you work on it, and also when you save, duplicate, rename or revert it (Apple). Apple does not say how long these versions are kept. If the PDF was cropped on another computer before it reached you, there is no earlier version on your Mac. If you use Time Machine, you can also restore an older copy of the PDF from a backup (Apple).

Apple’s guide only documents Undo Crop and Revert To for getting a cropped PDF back. It does not say how other apps treat a page cropped in Preview.

A crop is not a redaction

Since the hidden parts are still in the file, never crop a PDF to remove sensitive information before sending it. Anyone who receives the file may be able to reset the crop and read what you hid. Remove the content from the source document instead, then export a new PDF.

Images inside PDFs

Resetting the page boxes only reveals what is on the page. If the PDF was made from a photo that had already been cropped and exported, the picture itself is flat, and no PDF tool can show more of it. In that case, follow the steps for the app that cropped the photo, such as Photos on iPhone and Mac or Word and PowerPoint.

When the crop cannot be undone

If Set To Zero shows nothing new and no earlier version exists:

1. Find the source file the PDF was made from, such as the original Word document or scan.
2. Ask the sender for an uncropped copy.
3. Restore an older copy from a backup, such as Time Machine on a Mac or OneDrive version history, which keeps earlier versions of PDFs for 30 days (Microsoft).
4. For a photo taken from the PDF, you can extend the picture for free on the uncrop.si home page. This adds new, generated pixels around it. It does not recover the cropped part, and it cannot recreate text. For the full list of options, see can you uncrop a photo?.