A common problem is that some users prefer metric units (kg,m,s) and others prefer US customary units (lbs, in, s). We welcome all calculations in any units but we recommend that people follow this method of making calculations so that they work in any system of units. However sometimes this is not possible if the calculation has been already made so we also feature this very useful ChangeUnits addin for Excel which makes conversion between units relatively easy although you will need to add a few extra formulas in cells.