geometry – Flexible and complete interface to document dimensions

The pack­age pro­vides an easy and flex­i­ble user in­ter­face to cus­tomize page lay­out, im­ple­ment­ing auto-cen­ter­ing and auto-bal­anc­ing mech­a­nisms so that the users have only to give the least de­scrip­tion for the page lay­out. For ex­am­ple, if you want to set each mar­gin 2cm with­out header space, what you need is just \usep­a­ck­age[mar­gin=2cm,no­head]{ge­om­e­try}.
The pack­age knows about all the stan­dard pa­per sizes, so that the user need not know what the nom­i­nal ‘real’ di­men­sions of the pa­per are, just its stan­dard name (such as a4, let­ter, etc.).
An im­por­tant fea­ture is the pack­age’s abil­ity to com­mu­ni­cate the pa­per size it's set up to the out­put (whether via DVI \spe­cials or via di­rect in­ter­ac­tion with PDF(La)TeX).