How to effectively reduce PDF file size

“Why is this PDF so large?” is a common question, and it can often be difficult to understand what is taking up space in a PDF. This guide covers how to audit the space usage in a PDF and gives suggestions of what to do about it.

Audit Space Usage

The Audit Space Usage tool in Adobe Acrobat is extremely useful in helping you understand which components of your PDF are contributing to the file size.

It can be found via File > Save as… > Optimized > Audit space usage…

In the scenario above, you can see that the PDF contains about 40 MB of images, and all the remaining metadata is negligible.

Reducing PDF Size with Acrobat

Adobe Acrobat comes with a feature called PDF Optimizer, which provides settings for reducing the size of PDF files.

Saving Considerations

Whenever PSPDFKit saves a PDF, it uses either incremental saving (faster) or a complete rewrite. Rewriting a document can reduce the file size, as unreferenced objects can be deleted.

Read more in our Growing PDF File Size guide.