How to flatten a PDF in Acrobat, Chrome, Preview or Sejda

Overview

Flattening a PDF converts every layer, form field or annotation into one non-interactive image so it uploads cleanly. You do this in Adobe Acrobat Pro or Reader, in Google Chrome, or with Sejda for files of 50 MB and less, before re-uploading to Flipsnack. The result is a flat file with no editable elements.

Before you flatten, three things to know

The result has no interactivity at all, and that includes hyperlinks. Links you still need can be added in Flipsnack after the upload, where they also become trackable.
Rename the file first, or save the flattened version under a new name. Flattening cannot be undone, and the original is the only copy that keeps your interactive elements.
Adobe Acrobat Pro flattens forms and interactive elements, not the image and text layers. If you need every layer merged, print to PDF from Chrome or Preview instead.

What does it mean to flatten a PDF file?

If you have problems with the conversion of your PDF: you cannot upload it, or you're missing elements after the upload, you might need to flatten the PDF. But what does that exactly mean?

To transform an interactive PDF into one flat layer that can’t be edited, clicked, or modified in any way after you export it.

Think of a flattened PDF file as a non-interactive document with a single layer, even though it may contain pictures, shapes, and text. In some cases, PDFs include interactive elements such as lead forms, markups, annotations, or image layers. For a successful PDF uploading in Flipsnack, you may need to flatten your file before the upload.

In short, you're exporting the file to a printer and saving it again as a simple PDF with no layers using Adobe Acrobat Pro. Or you can use free alternatives like Sejda or Google Chrome.

💡 Benefits of flattening a PDF before you upload it

Layers, transparency and form fields are what convert unpredictably: flattening removes all three at once, which is why a failed upload usually goes through afterwards.
No element silently dropped: the pages your readers see match the PDF you approved.
Chrome and Preview do it for free: so a failed upload is not a reason to buy Acrobat.
Flatten a copy: the interactive original is still there when you need it back.

Which method to use

All four produce a flat PDF. They differ in what you have installed and what you are willing to lose:

Adobe Acrobat Pro or Reader: the most control, and the only route that lets you flatten annotations and form fields selectively. Use it if you have Acrobat.
Google Chrome: free, installed everywhere, no account. Open the PDF, print it to PDF. Good for most files.
Preview on macOS: the same idea without leaving the Mac. Open the PDF, then File → Print → PDF → Save as PDF.
Sejda: browser-based, nothing installed, capped at 50 MB per file. Use it when you cannot install anything.

Using Adobe Acrobat Pro and Adobe Acrobat Reader to flatten PDFs

The steps for both Adobe Acrobat Pro and Adobe Acrobat Reader are the same:

Open Adobe Acrobat Pro and import your PDF file.
Go to Tools, found either at the top left or at the right section of the screen, and click on Print Production.

From here, head on to the Preflight tab.

A pop-up window will open, from where you can choose the elements that are present in your file (e.g., annotations and form fields).

Click on Analyze and fix.
Next, you’ll have to (re)save the file. Your PDF file is now flattened.

Using Google Chrome to flatten PDF files

With this browser’s help, you can successfully transform modifiable PDFs into flat documents.

Open a Google Chrome window and drag your PDF file into it.
Click on the Print icon in the top-right corner.

In the new window that pops up, go to Destination.
Choose Save as PDF from the drop-down and click on Print to flatten the file. Your flat PDF file is now saved on your device.

Using Sejda to flatten PDF files of 50 MB and less

Sejda is a web-based tool that helps flatten PDF files online by turning them into scanned pages (all layers included).

Access their website and search for the Flatten option.

Upload your PDF file (make sure it doesn’t exceed the 50 MB limit).

At this stage, either choose to Flatten everything or just Flatten form fields, depending on what you need to use in the converted PDF.
After you click the Flatten PDF button, it’ll just take a few moments to complete the process.

Download your flat PDF file, and you’re done.

If you still encounter issues with uploading your flat PDF file on Flipsnack, please contact us via live chat to help identify and fix the problem together.

How to tell whether it worked

A flattened PDF looks identical. What changes is what you can do to it:

Open it and try to click a form field or a link. Nothing should respond.
In Acrobat, Tools → Edit PDF shows the page as a single image rather than separate text and object layers.
Text usually stays selectable, so do not use that as the test. Flattening removes interactivity and layers, not the text itself, unless the method rasterised the page.
The file size usually changes, which on its own tells you the file was rewritten.

Additional tips / FAQs

Does flattening reduce the file size? Not reliably. It can go either way depending on the method, and a rasterised page is usually larger. If size is the problem, the size guidelines are the place to start.
Will I lose my hyperlinks? Yes. Flattening turns links into ordinary pixels. Add them again in Flipsnack after the upload, where you can also track the clicks.
Can I undo it? No. Keep the original file and flatten a copy.
Do I have to flatten every PDF before uploading? No, and most do not need it. Flatten when the upload fails or when elements go missing after conversion.
Does flattening change how the text looks? It should not. If fonts shift, the font was not embedded in the original, so fix that before flattening.
Is flattening the same as printing to PDF? In practice, for this purpose, yes. Printing to PDF from Chrome or Preview produces a flat file. Acrobat's Preflight is more precise about what it flattens.
My PDF still will not upload after flattening. The problem is elsewhere: size, page count, or a corrupt file. Common PDF conversion issues covers each.

Next steps

Need expert support?

Our team is here to help. Connect with our team experts or message us via the live chat for personalized assistance.