Less than half a latte
Starbucks makes its Matcha Latte from its matcha, milk and classic syrup. Matcha is powdered green tea, whisked into the drink rather than steeped and strained out, which gives it more caffeine than most tea drinks but still far less than coffee. A Grande carries 65 mg, against 150 mg in a Grande Caffè Latte and 315 to 390 mg in a Grande Pike Place Roast.
Unlike the espresso drinks, matcha scales with the cup: 20 mg in a Short, 45 mg in a Tall, 65 mg in a Grande and 85 mg in a Venti. The iced version tracks it closely, with 40 mg in a Tall, 65 mg in a Grande and 85 mg in the 24 oz iced Venti.
Against the other tea on the menu
Starbucks lists 40 mg for its brewed black teas, Royal English Breakfast and Earl Grey, at every cup size, and 16 to 25 mg for a Grande of its Emperor’s Clouds & Mist green tea. So a Grande matcha carries more than any brewed tea of the same size on that menu, and slightly more than a Grande Chai Latte (55 mg). Against home-brewed green tea, which USDA puts at 29 mg for an 8 oz cup, a Grande matcha is a little over two cups.
Who it suits
For someone cutting back from coffee, a matcha latte is a real reduction: switching a daily Grande Pike Place for a Grande matcha removes 250 to 325 mg of caffeine. At 65 mg it is also well under the 200 mg single dose that EFSA assessed as safe for healthy adults, and a small fraction of the 400 mg daily figure the FDA cites.
For someone avoiding caffeine, it is not a caffeine-free drink. Two Venti matcha lattes, 170 mg, come close to the 200 mg daily ceiling ACOG uses in pregnancy. And with caffeine’s mean half-life of about five hours (NCBI), an evening matcha still counts toward the night.