Report designer generate report not fit to paper size

I have a report which have header that have height 2 cm , body 25 cm and footer 2.97cm , the total is 297mm, which is the height of A4 paper. However, when the report comes out. The content is always shift which is not fit to A4 size. Any way that I am not correct?

You also need to consider the top and bottom margins (and printer requirements) as set in Format->Page.