250 grams of powdered sugar is 8.82 oz (250 g) in weight, which fills 1.89 cups (446 mL). When poured into a loose pile, it is about the size of a water bottle.

In kitchen measures
1.89 cups
90.6 tsp · 30.2 tbsp · 1.89 cups
about the size of a water bottle
Powdered sugar typically ranges 0.5–0.62 g/mL depending on how it's packed. A firmly packed scoop weighs more.