How many grams in a cu of flour?

For some other easy conversions: 1 cup of sugar = 200 g, 1 tablespoon butter = 15 g

I tend to use 120 g per cup of flour since it's easier to divide for 1/4 and 1/3 cups. But, as Susan W states, it's different for different types of flours.

The standard answer for ap flour is 125, but it can change with type, brand and even humidity.