How much you feed your cat depends a lot on how old your cat is, how much your cat weighs and how active it is, as well as the quality of cat food you are feeding it.
To get a general guideline look at the back of your cat food bag to see a Daily Feeding Guide. For instance, Science Diet dry cat food recommends that an adult cat age 1-6 years should get the following daily amount of dry cat food:
~ 5 pound cat should receive 1/4 - 3/8 cups per day
~ 10 pound cat should receive 3/8 - 5/8 cups per day
~ 15 pound cat sould receive 5/8 - 3/4 cups per day
As they note on the bag, "These ranges are a starting point only. Your pet may need less or more food to maintain proper weight. Adjust as needed"
Source(s):
Science Diet daily feeding guide:
http://www.gotknowhow.com/articles/gallery/30/53
General rules to help you determine how much to feed your cat:
http://www.gotknowhow.com/articles/how-much-food-s...