When is this the right tool?

When a document must look identical everywhere, and you have accepted losing the text layer.

Will the file get smaller?

Usually not. For a text document it typically grows. The tool reports the actual sizes.

optimize

Rasterize a PDF

Turn every page into a flat image, so it looks the same everywhere.

Runs in your browser

How it works

Rasterizing removes everything interactive and everything a reader might interpret differently: fonts that may not be available, form fields whose appearance is generated, annotations, layers. What is left is a picture of each page, which looks identical in every reader. The costs are that text stops being text, accessibility is lost, and the file usually gets larger — for a text document, considerably larger.

Related tools

Flatten Form

/flatten-pdf-form

Compress PDF

/compress-pdf

Grayscale PDF

/grayscale-pdf

Questions

When is this the right tool?: When a document must look identical everywhere, and you have accepted losing the text layer.
Will the file get smaller?: Usually not. For a text document it typically grows. The tool reports the actual sizes.
Can it be undone?: No. Keep the original.