How much compression do I need? There is no absolute answer but generally the lowest compression necessary to do the job. If you wear compression stockings to control swelling in the legs, measure your ankles first thing in the morning when they are normal. Measure again at the end of the day when you have noticeable swelling. If there is more than Â½ inch difference by evening, then 20-30 mm/Hg pressure is most likely what you need.