Hi there.
This may be an odd question for some, but nevermind please.

I want to draw some figures and then print out.
Size should be 28mm for miniatures.
Now i don´t really know how to set the size right in Inkscape.

Any help is welcome!

Go to the Document properties page under File -> Document properties (ctrl+shift+D). Here you can define what units of measurements you want to use for a lot of things. You can change the page size to a specific size, or use guides or a grid to create a canvas of the proper size. As an alternative, perhaps even an easier one, you could use the rectangle tool ( ) to create a rectangle of the proper size and draw within it. Just be sure to delete the rectangle if you don't want it to print as well.

If I'm not mistaken, if you create a square 28 x 28 mm like this, it will print out in that size as well if you print directly from Inkscape.

Welcome to InkscapeForum!

First let me mention the info in my forum signature. Lots of great instructional materials

Inkscape opens by default at 35% zoom. First you'll probably want to make it 100% (use the Zoom tool ) Next, since it sounds like you need the rulers in mm, you'll have to change the Inkscape default units. Please go to File menu > Document Properties > Page tab > General > Default Units. And even though you're changing default units, that doesn't change the units everywhere within Inkscape (I don't know why). So whenever you come across units that aren't in mm, look around on the Inkscape window and you'll find a place to change them. (It will be a tiny dropdown menu.)

Now for page size. The same Doc Props tab, look further down for Page Size. You could change the page size either before you make the drawing, or after, whatever you prefer. I'm not clear if you need the size to be 28 mm X 28 mm, with one figure on each page? Or if you just need it to be 28 mm height, and as wide as however many figures you need to draw. If you change the page size before you draw, choose one of the templates from all the many listed under Page Size in Doc Prop. Or you can set a custom size, just below that. If you wait until you're finished drawing, you could use Select All (Edit menu or Ctrl Z) then open Doc Prop > Custom Size > Resize page to content > Resize page to drawing or selection. As you can see there, you can set a margin if you want.

And finally, note the Page Border that you see on the Inkscape canvas. That's just a guide and does not show up on the finished image. It's good to have the guide showing, because if any of your drawing is outside the border, it might not print (depending how to get to the printing stage) or if you put it on the internet, might not show up. However, some people do find it annoying to their drawing process, so you can disable it and re-enable as needed. These are controlled by checkboxes at the bottom of the same Page tab of Doc Prop dialog.

Thanks a lot you two for the nice welcome and fast and competent responses.

I´m actually creating paperminis for our tabletop game. So i want the figures to be ca 28mm high and 25mm broad, then after drawing mirror them to make a backside. Best is as many as possible on one page, printing toner and cardstock aren´t really cheap here.

Your answers help me already quite a lot, will try it in the evening.