Paragraph space-after units

Hi Tim:

Welcome to InDesign and to the community forum.

You can override the default measurement system by typing in two letters after a value, i.e., in, mm, cm, pt, etc.

For example, if you are working in millimeters and want to specify 6 pts of space above a paragraph (in the Properties panel, the Control Panel or the Style Options dialog box—wherever one types in spacing values), type in 6 pt. When you press Tab, InDesign will convert that value to the mm equivalent—2.117 mm. 

You may find it easier in the long run to do the opposite—set InDesign to measure in Picas—where 0p6 indicates zero picas, 6 points—and then use the override when you are specifying larger values by typing in mm.

~Barb 

If you're new, a tip: never change values in the paragraph or character palette. Use Styles in all cases. I don't really know why those palettes are even there, unless it's to create work and waste time.