Cat food carb calculator
How many carbs are in your cat’s food?
Copy the guaranteed analysis from the side of the can or bag. You’ll see the carbs the way vets and diabetic-cat owners compare them: as a share of calories.
Carbohydrates
—% of calories
- Carbs as fed
- —
- Carbs dry matter
- —
- Protein dry matter
- —
- Phosphorus
- —
How to calculate carbs in cat food
Pet food labels list protein, fat, fiber and moisture, but not carbohydrate. Whatever is left after those, and after ash (the mineral content), is mostly carbohydrate:
carbs = 100 − protein − fat − fiber − moisture − ash
Because a can is mostly water, that number always looks tiny. So the next step is to ask how much of the food’s calories come from carbohydrate. Protein and carbohydrate give about 3.5 calories per gram and fat about 8.5, the standard values used for pet food.
Worked example
A pâté label reads protein 11%, fat 5%, fiber 1%, moisture 78%, with no ash listed.
- Assume ash of 2.5%: 100 − 11 − 5 − 1 − 78 − 2.5 = 2.5% carbs as fed.
- Calories from each: protein 11 × 3.5, fat 5 × 8.5, carbs 2.5 × 3.5.
- Carbs are 9.7% of calories, just under the 10% low-carb line.
Label values are minimums and maximums, not exact amounts, so treat the result as a close estimate. If your cat is diabetic, change food only with your vet: insulin needs can drop within days. The lowest-carb can we compare right now is Blue Buffalo Chicken Recipe; see the full low-carb wet cat food list.
Questions about carbs in cat food
How do you calculate carbs in cat food?
Take 100 and subtract the protein, fat, fiber, moisture and ash percentages from the guaranteed analysis. If ash isn’t listed, 2.5% is a fair guess for wet food and about 7% for dry. What’s left is roughly the carbohydrate.
What is a good carb percentage for cat food?
Many vets and diabetic-cat owners aim for under 10% of calories from carbohydrate. Most canned pâtés land under that line; most dry foods are well above it.
Why does wet food show so few carbs “as fed”?
Because a can is mostly water. 2% carbohydrate as fed can still be 10% of the calories. That’s why we compare by share of calories, which ignores water.
Can I use this calculator for dry cat food?
Yes. A typical dry food (32% protein, 14% fat, 10% moisture) comes out around 34% of calories from carbohydrate, several times what most canned pâtés have.