40 grams of cocoa powder is a measurement that fills 4.51 tablespoons. When poured into a loose pile, it is 3.18 in wide and 1.54 in tall, which is about the size of a large egg.

In kitchen measures
4.51 tablespoons
13.5 tsp · 4.51 tbsp · 0.282 cups
about the size of a large egg
Cocoa powder typically ranges 0.5–0.7 g/mL depending on how it's packed. A firmly packed scoop weighs more.