In cat food, "dry matter" refers to the nutrient content of the food after all the moisture is removed, allowing for a more accurate comparison of nutrient profiles between different types of cat food, especially wet and dry.  Wet, of course, has much more moisture than dry foods.  Comparing nutrient percentages as fed, can be misleading because the water content dilutes the other nutrients in wet food.  Dry matter analysis removes the water content from the equation, allowing you to compare the actual concentration of protein, fat, and fiber.  


 

Here is how you calculate:   1) Subtract the moisture content from 100%. In this example 100% - 75.9% = 24.1% dry matter. 2) Convert individual nutrients from “as fed” to “dry matter”. Divide the “as fed” percentage of a particular nutrient by the dry matter percentage calculated in step 1.

 

Calculating Calories

 

To figure out how many calories per day your cat needs, your veterinarian will do a calculation based on the factors discussed above, using your cat's weight in kilograms and their body condition score. A general guide to go by is that cats should eat about 25 to 35 calories per pound of body weight.

 

Calculating Carbs

 

Calculate carbohydrate content: Add protein, fat, fiber, moisture, and ash, and subtract that sum from 100. If ash is not listed estimate 2% for wet food and 6% for dry food. This food has 3% digestible carbs. These are the carbs with calories.