Ug is microgram, one thousandth of gram, and the symbol is ug. Mg is mg, which is one millionth of a kilogram. The symbol is Mg. The relationship between ug and mg can be expressed by the following mathematical formula: 1mg= 1000ug, 1mg equals 1000 microgram. Use this formula to convert ug into mg. The calculation result is: 1ug is 0.00 1mg. 10ug is equal to 0.0 1000000000002mg.