Q. Hello Rav, I know playing games on Shabbat is not the best thing, but if one is playing a game and needs to measure time (eg. 60 seconds), is it permissible to do so by looking at a clock?
Thanks.
A. Indeed, you are right one should use the time available during Shabbos for learning Torah and Avodas Hashem.
Poskim permit using during Shabbos a watch or clock (Mishna Berura 308: 168 and others), this is because just looking at them to know the time, does not involve an act of measuring. However, when there is a visible act of measuring, it may be different.
39 Melochos (V. 4, p. 979) writes: “Even measuring (i.e. calculating) time is forbidden. For example, one may not use a watch to measure how many seconds it takes to answer a game quiz.”
Horav Shlomo Miller’s Shlit’a opinion is that one can use a fixed clock for measuring that time since no hand movements showing measurement are involved.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a