How to automatically trim white margins from a PDF

1 min read·23 July 2026

Scanned documents often have wide white borders that waste space. With the automatic trimmer on PDFrust you remove those borders in one click, without entering measurements manually.

Why are those white margins there?

When scanning an A4 sheet, the scanner often captures an extra margin around the page. Some PDF export programs also add default white margins. Those borders look unprofessional in presentations and e-readers and increase the file size.

How does auto-trim work?

The tool analyses each page and detects the outermost edge of the content. It then crops the white space down to a small safety margin. You can set the margin yourself if you want to keep a little breathing room.

Trim PDF margins

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What if my pages have different sizes?

The tool processes each page independently. Pages with more text or larger images are cropped to a different final size than empty or short pages. If you want a consistent format, use the manual crop tool instead.

Will I lose content?

No, as long as the safety margin is large enough. The tool detects pixels darker than a threshold and keeps everything within that area. Make sure you check the preview before downloading.