I'm creating a rectangle and then change its size typing the dimensions (mm) on the tool bar, lets say 170mm width.
If I place a ruler on my monitor screen its about 150mm! (zoom level 100%) On a random ruler webpage things look fine.
What do i miss here?
Have you already calibrated your rulers? (Tools / options / Wotkspace / Toolbox / Zoom, Pan tool / "Calibrate Rulers"
No I haven't. I meant a physical ruler not the digital one. Zoom relative to 1:1 is checked.
Do I really have to measure my monitor?
Yes, using a physical ruler and adjusting the rulers, accorging the "Calibrate Rulers" options.