The answer is not easy because each cat is different in terms of weight and activity and the advice varies anyway. Also we have wet and dry cat food which greatly complicates things. Incidentally there is a page on PoC about converting wet to dry – reading cat food labels.
The information here is generalised. I welcome alternative thoughts.
The catinfo website (run by a vet and strong on cat nutrition) says that about 5.5 ounces of wet cat food is required daily for an adult cat. This figure seems slightly low to me. However, the amount varies amongst cats because of different metabolic rates and activity levels.
An adult cat needs about 30-35 calories per pound of body weight per day so a 10 pound cat needs 300-350 cals. This may be a bit high based on the advice of other “experts” on other websites; perhaps between 200-350 cals with an optimum at around 230 cals daily (perhaps).
Inactive cats and perhaps neutered cats need less.
On cat food boxes, manufacturers in the UK, state that an 4 kg cat (around 9 pounds) needs 200-300 grams of wet cat food (7-10 ounces) per day.
As dry cat food contains very little water the equivalent weight of the food is less. The manufacturers state that 100 grams of wet food is the equivalent of 20 grams of dry or about 60 grams per day. This makes about 2.2 oz. of dry daily for a 10 pound cat (input welcome on this).
You’ll have to work out the calorie content if providing a raw diet and then work out the weight. Raw cat food is probably more dense and calorific but I am not sure.