Understanding Dry Matter Basis in Pet Food
If you've ever tried to compare a can of wet dog food to a bag of dry kibble by looking at the "Guaranteed Analysis" on the label, you've probably been wildly misled. A can of wet food might boast "10% Crude Protein," while a bag of dry kibble claims a massive "30% Crude Protein." To the untrained eye, the kibble looks three times as nutritious.
However, this is a mathematical illusion caused by moisture content. To make an accurate, apples-to-apples comparison between any two pet foods, you must use a formula called the Dry Matter Basis (DMB).
What is Dry Matter Basis?
Pet foods vary drastically in how much water they contain. A typical dry kibble is about 10% water. A typical can of wet food is about 75% water (or more!). Water contains zero protein, zero fat, and zero carbohydrates, but it makes up the vast majority of the weight in a can of wet food.
Dry Matter Basis is the mathematical process of virtually "removing" all the water from the food so you can evaluate the actual nutritional makeup of the dry matter left behind.
How to Calculate DMB
Don't worry, you don't need an advanced math degree. Here is the simple formula:
- Find the Moisture % on the Guaranteed Analysis label.
- Subtract the Moisture % from 100 to get the Total Dry Matter %.
- Find the nutrient you want to evaluate (e.g., Crude Protein %).
- Divide the Nutrient % by the Total Dry Matter %, then multiply by 100.
Let's Look at an Example
Canned Food Label: 10% Protein, 75% Moisture.
- 100 - 75 (Moisture) = 25% Dry Matter.
- (10 / 25) x 100 = 40% Protein on a Dry Matter Basis.
Dry Kibble Label: 25% Protein, 10% Moisture.
- 100 - 10 (Moisture) = 90% Dry Matter.
- (25 / 90) x 100 = 27.7% Protein on a Dry Matter Basis.
In reality, the wet food that initially looked like it had very low protein actually contains significantly more protein than the kibble once the water is removed from the equation!
Why This Matters
Veterinarians frequently recommend specific dietary ratios to manage health conditions. For example, a cat with kidney disease needs low phosphorus, or a dog with pancreatitis needs a strictly low-fat diet. If you just read the front of the label without converting to DMB, you could easily feed your pet a diet that actively worsens their condition.
Save yourself the math by using our free Dry Matter Basis Calculator. Simply plug in the numbers from your pet's food label, and instantly see the true nutritional value. By understanding DMB, you elevate your pet parent skills and ensure you are always making informed dietary decisions.