Dry matter basis means you subtract the water from both foods before you compare anything. Take the protein number off the label, divide it by the food's dry matter (100 minus the moisture percentage), and you get a figure you can hold up against any other food. A gently cooked blend listing 5% protein at 70% moisture is really about 17% protein. A dry food listing 26% at 10% moisture is about 29%. Now the two are on the same scale.
Why the printed numbers can't be compared straight across
Every guaranteed analysis on every bag, roll, and tub is printed "as fed." That includes whatever water is in the product. Dry food carries very little. Gently cooked food carries a lot, because muscle meat, squash, and green beans are mostly water to begin with.
Read the labels side by side without converting and fresh food looks like it has a fifth of the protein. It doesn't. You're looking at dilution.
The two numbers you need before you can do anything
Find crude protein and find moisture. Both are required on the label by state feed regulations, so they're always there, usually in a small box on the back or side.
Dry matter is the leftover: 100 minus moisture. At 70% moisture, dry matter is 30%. At 10% moisture, dry matter is 90%.
The arithmetic, done slowly
Divide the as-fed nutrient by the dry matter, expressed as a decimal.
Fresh blend, 5% protein, 70% moisture: 5 ÷ 0.30 = 16.7% protein on a dry matter basis.
Dry food, 26% protein, 10% moisture: 26 ÷ 0.90 = 28.9%.
Same trick works for fat, fiber, and ash. It works for calcium and phosphorus too, if the label guarantees them.
A worked conversion table
Notice what happened. The protein gap shrank from a five-fold difference to a modest one. The fat gap nearly closed. Fiber stayed lower in the fresh food, which is real and worth knowing.
Guaranteed analysis is a promise, not a measurement
Crude protein is listed as a minimum. Crude fat is usually a minimum, fiber and moisture are maximums. So the actual batch often runs above the printed protein floor and below the printed moisture ceiling.
So dry matter math gives you a fair comparison, not a precise one. Treat the result as a range. For true analyzed values, ask the manufacturer for a typical nutrient analysis.
Calories are the other half of the story
Two foods can land in the same place on dry matter protein and still feed completely differently, because caloric density drives portion size. Dry food commonly runs 350 to 450 kcal per cup. Gently cooked food runs far lower per unit volume, since a good part of the volume is water.
Look for the metabolizable energy statement, usually given in kcal per kilogram and kcal per cup or per package. That number, not the protein percentage, tells you how much to put in the bowl.
Where the math stops being useful
Dry matter basis says nothing about digestibility. It doesn't distinguish protein from muscle meat versus protein from a plant concentrate. It won't tell you whether the amino acid profile is complete or whether the fat carries usable omega-3s.
For that, you're reading the ingredient panel and the nutritional adequacy statement. The AAFCO consumer guide to pet food labels walks through what each part of the label legally means, and the FDA's page on complete and balanced claims explains how a food earns that phrase in the first place.
How gently cooked blends read after conversion
Convert a My Perfect Pet beef blend or the chicken and beef blend and you land in a moderate-protein, moderate-fat range that sits comfortably next to premium dry food. The difference shows up in the ingredient list and the cooking method, not in some dramatic nutrient gap.
Owners comparing across the whole My Perfect Pet lineup can run the same conversion on each blend. A reduced-carb formula and a controlled-phosphorus formula will convert to noticeably different profiles, which is the point of having both.
Special diets need more than a percentage
If your dog has been prescribed a phosphorus or protein ceiling, dry matter percentages are the starting point of a conversation, not the answer. Controlled-phosphorus blends are foods formulated with limited phosphorus. They are not a therapy, and no label conversion replaces a diagnosis.
Bring the label, the converted numbers, and your dog's recent bloodwork to your veterinarian and let them set the target. The WSAVA global nutrition guidelines include the questions a clinician will want answered.
A quick example with a real dog
Say you have a 42-pound mixed breed eating 2 cups of dry food a day at 380 kcal per cup, so roughly 760 kcal. Switching to a fresh blend at, hypothetically, 1,200 kcal per kilogram means about 630 grams daily, or a bit under a pound and a half.
Volume looks enormous next to two cups of kibble. The calories match. That gap is water, and it's the most common reason owners think they're overfeeding in week one.
FAQ
How do I calculate dry matter protein if the label only gives a moisture maximum?
Use the maximum as your moisture figure. It slightly understates the dry matter protein, which errs conservative. If you want the real number, request the typical analysis from the company.
Is 17% protein on a dry matter basis low for a dog?
It's in a normal adult maintenance range. Growth, heavy work, and some medical situations call for more. Your vet can tell you where your specific dog should sit.
Do I need to do this math for treats too?
Not usually. Treats should stay a small slice of daily calories, so their nutrient percentages barely move the total. Watch their calories instead.
Why does fresh food cost more per calorie if the dry matter numbers are similar?
Because you're paying for whole muscle meat, gentle cooking, cold storage, and refrigerated shipping. The nutrient math converges. The production cost doesn't.