I have a glass that has measurements in it, can I use it in Shabath?
Since we are not allowed to measure things on shabbos, therefore if the primary use of this cup is for measuring then it is a kli shemiplachto l’issur. (If it is used mostly for permitted usesthen it wold be permitted to use it for any use on Shabbos.) The halacha of a li shemilachto l’issur is that it can be used on shabbos for a permitted use, such as if you don’t have another suitable cup to drink from, you are allowed to use that glass. Additionally if you need to measure something that is a dvar mitzva, i.e. to measure the amount of wine needed for kiddush, or medication for a sick person, then you can use it even for measuring. The reason being that we are allowed to measure things for a mitzva use.
O:CH 308-3, 323-1, Minchas Shabbos 88-25,