There is a Polish website https://kalkulatorkuchenny.pl/, where you type, say, 1 teaspoon of sugar (łyżeczka cukru) and it will convert it to mass, volume, spoon and number of glasses. I’m pretty sure, there is an English language alternative, but didn’t find any
I didn’t read carefully, sorry. Anyway, you can specify the type of flour there, so it’s a bit more precise