I'm about to print my thesis (A4 size) and the publisher has requested me to extend the size of each side of page in 3 mm, so the paper cutter can do its thing properly. I can't change the size of the whole project as it would ruin the lay out so, how could I add this extra size in all pages?
Just in case I haven't made myself understood, I attach a picture of the desired process from the current state (left) to the goal (right). Thanks.

\addtolength\oddsidemargin{3mm}\addtolength\evensidemargin{-3mm}. This also accounts for double sided printing. If you are doing single sided, then you want both even and odd to be+3mm. – Steven B. Segletes Sep 10 '19 at 10:56\documentclass{book} \usepackage{lipsum} \begin{document} \lipsum[1-9] \clearpage \addtolength\oddsidemargin{30mm}\addtolength\evensidemargin{-30mm} \lipsum[1-9] \end{document}– Steven B. Segletes Sep 10 '19 at 11:08\geometry{bindingoffset=3mm}from the eponymous package? – Bernard Sep 10 '19 at 11:13