This is elementary to science trained people but that isn't everyone. Weigh your empty new pot. Fill it with water on your scale, then subtract the first number from the second one. If using ounces, that number is also the ounces of volume. If using grams, that number is also the milliliters of volume. For our purpose, the weight of the water and the volume of the water are the same at room temperature. Measuring one gives both weight and volume. A pint(16 oz.) of water is a pound(16 oz.) of water at room temps. A liter (1000 milliliters) of water is a kilogram (1000 grams) of water.
