≈ 0 mg
Filter coffee is about 90–110 mg a mug; the brew and the amount of coffee change it.
A single espresso shot is usually 60–80 mg.
An Americano carries as much caffeine as its shots; many cafés use two.
In a latte or cappuccino the shots set the caffeine, not the milk.
Black tea is about 55 mg a mug and 30–55 mg a small glass, depending on the brew.
A mug of green tea is usually 20–30 mg.
A serving of matcha (about 2 g of powder) is usually 40–70 mg.
Decaf isn't zero: about 2–15 mg a mug.
A 330 ml can of cola is about 33 mg; diet versions can be a little higher.
Energy drinks are usually 80 mg per 250 ml; large cans hold twice that.
50 g of dark chocolate is about 25 mg; more cocoa, more caffeine.
A cup of Turkish coffee is usually 50–65 mg; the beans, the grind and the water change it.