Dry Matter Calculator
Use this dry matter calculator to find the dry matter basis percentages of your pet food so you can easily compare it with another brand.
I want to...
Guaranteed analysis - Product 1
Introduction / overview
The Dry Matter Calculator converts the "as-fed" nutrient percentages listed on your pet food's guaranteed analysis into dry matter basis percentages — essentially stripping out the water so you can compare products apple-to-apple.
🐾 Here's the thing: one brand might advertise "30% protein" with 2% moisture, while another says "25% protein" with 30% moisture. On a dry matter basis, that second brand actually has more protein. This calculator reveals the real numbers.
Who is this for?
- Pet owners who want to make informed decisions about their dog or cat's food.
- Multi-pet households comparing different brands or formulas side by side.
- Pet nutrition enthusiasts who dig past the marketing to understand what's really in the bag.
The calculator uses the standard dry matter conversion formula, which is widely accepted in veterinary nutrition. If you're also tracking your pet's calorie intake, check out our Cat Calorie Calculator or Dog Age Calculator for a fuller picture of your pet's health.
How to use / quick start
- 1Select your mode – choose "check a product" for a single bag, or "compare 2 products" to put two brands head-to-head.
- 2Enter the as-fed values from the guaranteed analysis panel on your pet food package: Protein, Fat, Fiber, and Moisture (all in percentages).
- 3Others is auto-calculated – the remaining percentage (typically carbohydrates, ash, and other nutrients) fills in automatically.
- 4Read the results table – the dry matter basis percentages appear below, showing the true nutrient content with moisture removed.
Pro tip: edit any field to reverse-calculate
The 5 input fields (Protein, Fat, Fiber, Moisture, Others) always sum to 100%. Try editing any of them — the calculator will automatically adjust the remaining field to keep the balance. This makes it easy to explore "what if" scenarios, like "what if this food had 5% less moisture?"
Step-by-step example calculations
Example 1: Converting a single product
Let's say you pick up a bag of dry dog food with this guaranteed analysis on the back:
| Nutrient | As-fed (%) |
|---|---|
| Protein | 30 |
| Fat | 12 |
| Fiber | 5 |
| Moisture | 10 |
Enter these into the calculator. Others is automatically computed as:
Now the calculator converts each nutrient to dry matter basis using the formula. For Protein:
The results table shows all nutrients side by side on a dry matter basis, making it clear how much of each nutrient your pet would actually get if the water were removed.
Example 2: Comparing two products
This is where the calculator really shines. Let's compare a dry food (low moisture) with a wet food (high moisture):
| Nutrient | Dry Food (as-fed) | Wet Food (as-fed) |
|---|---|---|
| Protein | 30% | 8% |
| Fat | 15% | 5% |
| Fiber | 4% | 1% |
| Moisture | 10% | 78% |
At first glance, dry food looks way more nutritious. But after converting to dry matter basis, the picture changes:
| Nutrient | Dry Food (DMB) | Wet Food (DMB) |
|---|---|---|
| Protein | 33.33% | 36.36% |
| Fat | 16.67% | 22.73% |
| Fiber | 4.44% | 4.55% |
🐕 Surprise: The wet food actually has more protein on a dry matter basis (36.36% vs 33.33%). Without this calculator, you'd likely assume the dry food was the better choice!
For Fat it's the same story — the wet food comes out ahead once you strip out the water. This is why veterinarians and pet nutritionists always recommend comparing on a dry matter basis.
Real-world use cases
1) Switching from dry to wet food
Your vet recommends switching your dog to wet food for dental reasons. You're worried about nutrient drop-off. Input the guaranteed analyses of both foods into compare mode — you'll likely find the wet food is more nutrient-dense on a dry basis than you expected.
2) Budget brand vs premium brand
The premium brand looks better on the shelf, but it's also more expensive. Enter both into the calculator and compare the dry matter percentages. Sometimes the budget option is surprisingly close once you factor out the water content difference.
3) Senior pet dietary management
Older pets often need higher protein to maintain muscle mass. Use the calculator to find foods that deliver the most protein on a dry matter basis. Combine this with our Dog Age Calculator to tailor nutrition to your pet's life stage.
4) Homemade diet formulation
Preparing homemade food for your pet and want to match the nutrient profile of a trusted commercial brand? Enter the commercial food's values, then tweak your homemade recipe's inputs until the dry matter percentages align.
Common scenarios
Comparing dog food brands
Most useful when you're considering a switch. Put your current food and the new candidate in compare mode to see the real nutrient differences. Pay special attention to protein and fat ratios.
💡 Works great with our Dog Quality of Life Calculator for a holistic view.
Evaluating cat food options
Cats are obligate carnivores and need specific protein levels. Use the calculator to ensure any new food meets the minimum protein requirements on a dry matter basis — especially when comparing wet and dry formulas.
Grocery store label decoders
Pull out your phone in the pet aisle and enter numbers directly from the package. No more guessing which bag offers better value — the calculator gives you the facts in seconds.
Veterinary diet assessment
If your vet has recommended a specific nutrient profile (e.g., low phosphorus for kidney disease), use the calculator to verify that the food you're buying actually meets those targets on a dry matter basis.
💡 Not a substitute for professional veterinary advice — always consult your vet for medical decisions.
Transitioning between food types
Moving from kibble to raw or from canned to freeze-dried? Moisture varies wildly across these formats. The calculator normalizes everything so you can maintain consistent nutrition during the transition.
Checking "grain-free" claims
Some brands market "grain-free" with higher protein, but Others (carbs) may still be high. Use the calculator to see the real carbohydrate percentage hidden in the "Others" field.
Tips & best practices
Always include "Others"
The "Others" field (mostly carbohydrates) is automatically calculated and essential for a complete picture. Most pet foods don't list carbs directly — this is the only way to see them.
Moisture matters most
The biggest difference between dry and wet food is water. A small change in moisture input can shift all dry matter percentages significantly. Double-check the moisture value on the package.
Check the total
Protein + Fat + Fiber + Moisture + Others should always equal 100%. If the numbers on the package don't add up (sometimes they don't!), adjust Others accordingly.
Use compare mode wisely
When comparing two products, enter both sets of numbers carefully. A typo in one field can throw off the comparison. Use the clear button to start fresh if needed.
Common mistake to avoid
Don't compare as-fed percentages directly! A food with 10% protein and 80% moisture is actually more protein-dense than one with 25% protein and 10% moisture once you convert to dry matter basis. Always use the DMB values for fair comparisons.
Calculation method / formulas
The dry matter basis conversion is a straightforward calculation. The idea is to remove the water and see what proportion of the remaining solid material is made up of each nutrient.
Core formula
DMB% = Dry Matter Basis percentage (the "real" nutrient content)
AFB% = As-Fed Basis percentage (what's printed on the label)
M% = Moisture percentage
Reverse formula
If you know the dry matter percentage and want to find the as-fed value:
Balance equation
All five input fields always sum to 100%. Others is computed as:
This "Others" category typically includes carbohydrates (by difference), ash (minerals), and any other nutrients not individually listed on the guaranteed analysis.
Related concepts
What is a guaranteed analysis?
A guaranteed analysis is the panel on pet food packages that lists minimum percentages of crude protein and crude fat, and maximum percentages of crude fiber and moisture. It's a regulatory requirement in most countries. However, these values are expressed on an "as-fed" basis, meaning they include the water content.
This is why two foods can look very different on the label but turn out to be nearly identical on a dry matter basis — or vice versa.
As-fed basis vs dry matter basis
As-fed basis is what you see on the package — the nutrient percentages including the moisture naturally present in the food. Dry matter basis recalculates these percentages as if all water were removed.
Think of it like comparing a fresh apple to dried apple slices. The fresh apple might be 85% water, so its "as-fed" sugar content looks low. But once dried, the sugar concentration is much higher. The dry matter basis gives you the true concentration.
Why this matters for your pet's health
Choosing food based on as-fed numbers can lead to unintentional under- or over-feeding of key nutrients. For example, a "high protein" dry food might actually have less protein than a "low protein" wet food once you account for moisture. Using dry matter basis ensures your pet gets the nutrition you're paying for.
This is especially important for pets with medical conditions (kidney disease, diabetes, allergies) where precise nutrient control is critical.
Frequently asked questions
What is a dry matter basis?
Dry matter basis is the percentage of nutrients in pet food calculated as if the moisture content were reduced to 0%. In other words, it's what you'd get if you dried the food until no water remained. This allows for fair comparison between foods with different moisture levels.
How do I calculate dry matter basis manually?
It's a three-step process: (1) Subtract the moisture percentage from 100% to get the dry matter percentage. (2) Divide the as-fed nutrient percentage by the dry matter percentage. (3) Multiply by 100%. For example, if a food has 30% protein and 10% moisture: . But it's much easier to just use this calculator!
Is it okay to add water to dry dog food?
Yes, it's perfectly fine and even beneficial! Adding water makes dry kibble easier to chew and digest, and it releases aromas that can make the food more appealing. Just don't add so much that you end up with soup — a splash is enough to moisten the kibble.
What does the "Others" category include?
"Others" is calculated by difference: 100% minus the sum of Protein, Fat, Fiber, and Moisture. It primarily represents the carbohydrate content (starches, sugars) along with ash (minerals) and any other nutrients not explicitly listed on the guaranteed analysis. For grain-free or low-carb diets, this number is especially worth watching.
Can I compare raw food to kibble using this calculator?
Absolutely — in fact, that's one of its best uses. Raw food typically has 65–75% moisture, while kibble is around 10%. Looking at the as-fed numbers, raw looks much lower in nutrients, but on a dry matter basis, they're often comparable or even superior. Use the compare mode to see for yourself.
What should I look for in a good pet food?
On a dry matter basis, look for at least 22% protein for adult dogs and 30% for adult cats (they're obligate carnivores). Fat should be around 8–15% for most adults. Fiber is typically 3–5%. But these are general guidelines — your pet's specific needs depend on age, activity level, and health conditions. Always consult your veterinarian for personalized recommendations.
Limitations & disclaimers
⚠️ Important disclaimer
This calculator is intended for educational and informational purposes only. It is not a substitute for professional veterinary advice. Nutritional requirements vary significantly between individual pets based on breed, age, weight, activity level, and health status. Always consult with a qualified veterinarian before making significant changes to your pet's diet.
Known limitations
- The calculator relies on the accuracy of the guaranteed analysis printed on the package. Manufacturers may have slight variations between batches.
- Guaranteed analysis shows minimums and maximums, not exact values. Actual nutrient content can vary.
- The "Others" category includes carbohydrates, ash, and any unlisted nutrients. It's a catch-all, not a specific measurement.
- Nutrient bioavailability (how well your pet can actually use the nutrients) is not accounted for — this is a chemical analysis, not a biological one.
Related Calculators
Cat BMI Calculator
Calculate your cat's Feline Body Mass Index (FBMI) using rib cage circumference and lower back leg length to help assess if your cat is at a healthy weight.
Dog BMI Calculator
Calculate your dog's Body Mass Index (BMI) based on breed, height, and weight to determine if they are healthy, overweight, or underweight.
Cat Pregnancy Calculator
The cat pregnancy calculator will compute the due date of your favorite feline.
Dog Life Expectancy Calculator
The dog life expectancy calculator estimates the age of your dog based on their breed and gives their average life expectancy.
Dog Age Calculator
Convert your dog's age to human years based on breed and size.
Dog Pregnancy Calculator
The dog pregnancy calculator provides you with your dog's due date.