May one use a measuring device to cook on Yom Tov?

Halachah certainly allows one to cook on Yom Tov, but the question arises as to whether measuring is permissible as part of the process of food preparation.

The chachamim forbade precise measuring on Yom Tov, but not making rough measurements. Therefore, it would be forbidden to use a measuring cup for the purpose of arriving at a precise amount. One may, however, use a measuring cup in order to roughly estimate an amount of rice. As long as one’s intent is to arrive at a general estimate and not to measure with precision, he may use a measuring cup to measure food.

Certainly, it is permissible to use an ordinary glass that does not have measurements, to determine the amount of rice that one wishes to prepare. Furthermore, Ha’Rav Ovadiyah Yosef (shlit”a) states that measuring is permissible for the purpose of a Mitzvah. Some people have the minhag of weighing Matzah at the Seder to know precisely how much they need to eat and some Hagadot include tables and diagrams to help a person determine the amounts of Maror and other foods he needs to eat. These measurements are permissible on Yom Tov, because they are made for the sake of a Mitzvah.