Do not confuse points with pixels
Pixels depend on the image resolution or render scale. A page rendered at scale 2 has roughly twice the width and height in pixels compared with scale 1, but the PDF page dimensions in points do not change.
Coordinates in these tools
Add Text, Sign and Redact accept distances from the displayed top-left in PDF points. Add Text and Sign use the unrotated page coordinate convention, so rotated pages need particular care. Redaction is placed on the rendered page, and the downloaded file must be visually checked.
Crop box versus deleted content
Crop PDF changes the visible crop box inside the page. It does not erase hidden material outside the box. Use redaction rather than cropping to remove sensitive information. Check every page size before applying one margin to a mixed-size document.
Try the related tools
Further reading
Updated 2026-10-18. These are implementation notes and practical explanations, not a conformance certificate.