15 grams of plant protein powder is 0.529 oz (15 g) by weight. It occupies 2.42 tbsp (35.7 mL) of volume and is about the size of a ping-pong ball.

In kitchen measures
2.42 tablespoons
7.25 tsp · 2.42 tbsp · 0.151 cups
about the size of a ping-pong ball
Density estimated by AI from typical values. Plant protein powder typically ranges 0.35–0.5 g/mL depending on how it's packed. A firmly packed scoop weighs more.