How many grams is 1 cup of mashed banana?

1 cup of mashed banana weighs

225g

That's 7.9oz. In a 250ml metric cup it's 238g.

This uses the US cup, the size American recipes mean. 1 cup is 237ml by volume.

Other amounts of mashed banana

Where these numbers come from

USDA FoodData Central, SR Legacy, food 09040: “Bananas, raw”. USDA lists these household measures for it:

1 cup, mashed = 225g
1 cup, sliced = 150g
1 extra small (less than 6" long) = 81g
1 small (6" to 6-7/8" long) = 101g
1 medium (7" to 7-7/8" long) = 118g
1 large (8" to 8-7/8" long) = 136g
1 extra large (9" or longer) = 152g
1 NLEA serving = 126g

Fractions of a cup are the cup weight scaled down. The tablespoon figure is the cup weight divided by 16, since USDA doesn't list a tablespoon for this ingredient. The teaspoon is a third of the tablespoon. Metric-cup figures assume a 250ml cup, and Australian tablespoons hold 20ml. Weights under 10g are rounded to 0.1g, everything else to the nearest gram. Full source list.