3,244. Calculating the Size of the Crop

Terumos 3:11

If produce is normally measured by volume, it should be measured by volume (prior to taking terumas maaser); if it’s normally weighed, it should be weighed, and if it can be counted, it should be counted. If it can be measured in any of these ways, it’s good to count it, better to measure it by volume, and best to weigh it.

Terumos 3:12

The mitzvah of terumas maaser is for a Levi to separate it from the tithes he receives, as per Numbers 18:26: “When you take the tithe of the children of Israel....” A Yisroel can take terumas maaser from the crop and give it to a kohein, and then give the maaser to a Levi after taking its terumah, which is a tenth of the tenth.