There are a variety of factors to consider when it comes to how much you should be feeding your cat. The first is the size of your cat - a larger cat will obviously need more food than a smaller one. Secondly, you need to take into account their activity level and whether they're indoor or outdoor cats. An active outdoor cat will require more calories than an indoor cat who spends most of their time sleeping!
Another important factor is whether your cat is neutered or not. Neutered cats tend to have a slower metabolism and so won't require as many calories as an unneutered cat. Finally, you also need to consider what type of food you're feeding them. Some foods are more calorie-dense than others, so even if you're feeding your cat the same amount by weight, they may be getting different amounts of calories.
The best way to determine how much to feed your individual cat is to use a calculator like this one from the American Society for the Prevention of Cruelty to Animals (ASPCA). Simply input all relevant information about your cat and it will give you an estimate of how many calories they need per day and how much food you should be giving them.