If only tealeaves or teabags are considered in calories point of view, then they have zero calories. This means that tea without milk and sugar has zero calories. When milk and sugar are added to tea, then the tea contain calories.

The amount of calories in tea depends upon the quantity of the milk and sugar added to the tea. Generally speaking, one teaspoon of sugar has 16 calories and one teaspoon of powdered creamer has 11 calories. More teaspoons of sugar and creamer added, more calories you drink.

So, if you're on diet, don't add too much sugar and creamer. If you want to work on your weight loss you should drink green tea. But remember low calorie tea is tea with not too much sugar and cream.

Iced tea is made from tea bag, water and ice cubes. So this means ice tea has zero calories. When sugar is added to Iced tea, then it gets calories. Commercial iced tea has higher calories than an iced tea because of added sweeteners.

One big cup of commercial mix iced tea has calories same as the calories in 4 cookies. Generally 1 cookie contains 50 calories. So one big cup of commercial iced tea would have almost 200 calories which is way too high.