One kilogram is approximately 2.20 pounds, so if you know something has 1000 kilograms of mass, to estimate how much it weighs in pounds, you can double it and then add ten percent of the doubled number, which is not that difficult to do, so 1000 + 1000 = 2000 then add 10% of 2000 or 200 so you get 2200 pounds. If you wanted a rougher estimate, you could just double the mass in kilograms to get a rough estimate in pounds.