First you need to know that 1 tsp = 0.1667 oz
So, if you take the number of ounces in the box of baking soda (found at the bottom of the box) and divide it by 0.1667 you'll get the number of...
It depends upon the brand and the size of the soda but a 20-ounce regular soda can contain 200 - 320 calories. Low-calorie sodas have less and diet sodas don't have calories.