There is some debate over the amount of caffeine found in tea vs. coffee, and among the various types of tea. Much of the confusion stems from a failure to consider the amount of tea leaves or coffee grounds used to make types of tea and coffee beverages.
Tea vs. Coffee
Ounce for ounce, tea leaves contain many times more caffeine than do coffee beans. However, whereas 1 oz. of coffee won't yield much more than 2 cups of coffee, an ounce of tea will yield as many as 20 to 30 cups, and that's assuming you don't go back for a second infusion. For that reason, a cup of tea almost always has less caffeine than a cup of coffee.
Green, White and Black Tea
Among teas, white is said to have the least caffeine and black the most. However, this may have more to do with the quantity and weight of leaves used. Because they are so much less processed, a tablespoon of white tea may weigh about the same as a teaspoon of black tea. And less leaves (in terms of weight) are generally required to make a satisfactory infusion of white tea compared with green or black.
What's in a Cup
According to Stash Teas, here is the breakdown in milligrams of caffeine for an average coffee and five types of tea: Coffee (5 oz. cup) 80 Black Tea (one tea bag) 40 Oolong Tea (one tea bag) 30 Green Tea (one tea bag) 20 White Tea (one tea bag) 15 Decaf Tea (one tea bag) 2
What's in a Cup
According to energyfiend.com, here are the caffeine contents of Starbucks beverages (8 oz. unless otherwise indicated). Brewed Coffee 180 Brewed Decaf Coffee 15 Caffè Americano 75 Caffè Latte (also Cinnamon Dolce Latte) 75 Cappucino 75 Caramel Macchiato 75 Espresso 75 (solo) 150 (doppio) Espresso Macchiato (also Espresso con Panna) 75 (solo) 150 (doppio) Frappuccino Blended Coffee (multiple flavors) 85 to 90 Frappuccino Light Blended Coffee (multiple flavors) 70 to 75 Tazo Black Tea Latte 50 Tazo Chai Tea Latte 50
As can be seen in the charts above, as a general rule, coffee has more caffeine than tea, black tea has more than green, and green more than white. But beyond that, there are many factors that can significantly affect actual caffeine levels.