Divide ounces by 1/16 to get the decimal amount in pounds, since there are 16 oz. to the pound. For example, 3 oz. equals 3/16, or 0.1875 lb. You can get the same result by multiplying the number of ounces by 0.0625.
Multiply the number of ounces by 28.349, the number of grams in an ounce, to get the decimal equivalent in grams. For example, 3 oz. equals 85.047 g, or 0.085047 kilogram.
Calculate the number of fluid ounces in a gallon by multiplying by 0.007812. For example, 3 fluid oz. equals 0.023436 gallons. You can get the same result by dividing by 128, the number of fluid ounces in a gallon. Multiply your result by 4 to get a decimal amount for the ounces expressed in quarts.
Multiply fluid ounces by 29.5735, the number of fluid ounces in a milliliter (ml), to get milliliters. For example, 3 fluid oz. equals 88.7025 ml, or 0.0887025 liters.