Interesting fact! Dry tea has more caffeine by weight than coffee. However, since more dried coffee is used than dry tea per cup, a cup of steeped tea contains significantly less caffeine than a cup of coffee of the same size. Most studies show that tea has between 40 and 120mg caffeine per eight ounce serving; whereas coffee has about 80-206mg caffeine per eight ounce serving. So even at the highest caffeine levels, tea has only half the caffeine content of a cup of coffee. Additionally, caffeine levels are directly related to how long a tea is steeped.
The longer a tea steeps, the higher the caffeine content. Another fact to consider is that caffeine in tea is different from that found in coffee.
Unlike coffee, tea leaves contain an amino acid called theanine, which works synergistically with caffeine to create a more balanced stimulative effect in the body. What this means is that rather than feeling a surge of energy then a sudden crash shortly after, as you sometimes do with coffee or other caffeinated beverages, you may feel a more gradual and revitalizing rise in energy that eventually balances itself out into a calmer, clearer and more focused state.
Facts courtesy of: