Given below is the True specific gravity formula, using this you can calculate the true specific gravity with the given steps. Subtract the weight of S.G bottle + powdered sample with the weight of S.G bottle. Again reduce the weight of S.G. bottle from weight of S.G bottle + water and divide the first and second step value. Now reduce the weight of S.G bottle + water + powdered sample with S.G bottle + powdered sample weight. Now subtract the obtained value by the divided value of first step.