Pet food dry matter calculator
Convert guaranteed-analysis percentages from an as-fed basis to a moisture-free dry matter basis, then compare one or two products fairly.
Guaranteed analysis
Enter percentages printed on the label.Product A
Required, 0 – 100.
Required, 0 – 100.
Required, 0 – 100.
Required, 0 – 99.99.
Product B
Required in comparison mode.
Required in comparison mode.
Required in comparison mode.
Required, 0 – 99.99.
Dry matter results
Moisture is mathematically removed.Product B is 5.10 percentage points higher in protein on a dry matter basis.
As-fed and dry matter comparison
| Measure | Product A as fed | Product A DMB | Product B as fed | Product B DMB | Difference (B – A) |
|---|
How to use the pet food dry matter calculator
What this calculator does
This calculator converts the percentages in a pet food guaranteed analysis from an as-fed basis to a dry matter basis (DMB). The conversion removes the mathematical effect of water, making it easier to compare a dry kibble with a canned, fresh, semi-moist, or rehydrated food. It is a composition comparison tool, not a complete judgment of food quality, digestibility, calorie density, ingredient quality, life-stage suitability, or medical appropriateness. The AAFCO explanation of as-fed and dry-matter values shows why moisture adjustment is needed before comparing label percentages.
When to use it
Use it when comparing wet and dry foods, checking whether a new food delivers a similar protein or fat concentration, translating a veterinarian's dry-matter target into a label comparison, or reviewing two products whose moisture guarantees differ substantially. It is also useful when a product already states a dry-matter analysis: enter its moisture as 0% to leave the listed nutrient percentages unchanged.
How to calculate
- Choose One product for a single conversion or Compare two products to place two labels side by side.
- For Product A, enter the label's Crude protein, Crude fat, Crude fiber, and Moisture percentages. Enter plain decimal numbers using a period, such as 12.5; the percent sign is already shown beside each field.
- In comparison mode, repeat the same four entries for Product B. Results update immediately after every valid change.
- Read the primary protein result, the dry matter percentage cards, and the comparison table. A positive value in the Difference column means Product B is higher; a negative value means Product A is higher.
- Select Download Excel to export the current inputs and typed numerical results to a validated workbook. Select Reset to restore the worked-example values shown initially.
Input guide
Comparison mode is required and accepts either one or two products. Crude protein, Crude fat, and Crude fiber are required percentages from 0 to 100; realistic examples are 30%, 6%, and 4%. Raising any nutrient while moisture stays fixed raises its DMB result proportionally. A common mistake is entering grams per serving instead of the label percentage. Moisture is required from 0 to 99.99%; 2% is used for Product A and 30% for Product B in the initial example. Higher moisture reduces the dry-matter denominator, so the converted nutrient percentages rise. Never enter 100%, because no dry matter would remain and division would be undefined. Each product's protein, fat, fiber, and moisture entries must not total more than 100%.
Output guide
Product A protein on a dry matter basis is the primary result and is an exact algebraic conversion of the entered label values, rounded to two decimals for display. Product A dry matter equals 100% minus moisture. Product A fat DMB and Product A fiber DMB apply the same moisture correction to fat and fiber. In comparison mode, Product B protein DMB and the live comparison statement show which product is higher after water is removed. The table's As fed columns repeat the entered label values, the DMB columns show moisture-adjusted values, and Difference (B – A) reports percentage-point differences. “Others” is a balancing estimate, not a measured nutrient guarantee.
Worked example
Product A starts with 30% protein and 2% moisture, so dry matter is 100 – 2 = 98%. Protein DMB is 30 ÷ 98 × 100 = 30.6122449%, displayed as 30.61%. Product B starts with 25% protein and 30% moisture, so its dry matter is 70% and protein DMB is 25 ÷ 70 × 100 = 35.71%. The comparison therefore reports Product B as 35.71 – 30.61 = 5.10 percentage points higher, even though its as-fed protein figure is lower.
Learn more
Pet food labels commonly provide minimum crude protein and fat and maximum crude fiber and moisture. Review AAFCO's guide to reading pet food labels to understand what those guarantees mean before treating them as exact composition values.
Formula and interpretation
Dry matter basis % = as-fed nutrient % ÷ (100 – moisture %) × 100
The denominator is the percentage of the food that remains after water is removed. A food with 75% moisture has 25% dry matter, so every as-fed nutrient percentage is divided by 25 and multiplied by 100. This does not create nutrients; it changes the reference basis from the food's total wet weight to the weight of its non-water portion.
Dry matter comparison is most useful for like-for-like nutrient concentration. It should be paired with calorie information, feeding directions, life-stage statements, and professional guidance when a pet has a health condition.
How to read guaranteed analysis values
A guaranteed analysis is not always a precise recipe breakdown. AAFCO explains that crude protein and crude fat are commonly guaranteed as minimums, while crude fiber and moisture are commonly guaranteed as maximums. That means the values can be conservative label limits rather than the exact amount in every batch. The AAFCO nutritional labeling overview describes these conventions and the role of laboratory analysis.
Because the guarantees mix minimum and maximum statements, the calculated “Others” remainder should not be interpreted as a precise carbohydrate value. Ash, soluble fiber, sugars, starches, organic acids, vitamins, and minerals may all contribute to the balance. For medical nutrition decisions, ask a veterinarian or board-certified veterinary nutritionist for a complete nutrient analysis, ideally expressed both per dry matter and per unit of metabolizable energy.
Common comparison mistakes
- Comparing as-fed percentages directly when moisture differs.
- Assuming a higher dry-matter percentage automatically means a better food.
- Using guaranteed maximum fiber or moisture as though it were an exact laboratory result.
- Ignoring calorie density and feeding amount; dry-matter concentration alone does not show how much a pet consumes per day.
- Using general label comparisons in place of veterinary advice for kidney, liver, gastrointestinal, urinary, allergy, obesity, or diabetic diets. Cornell's veterinary guidance, for example, discusses fiber targets on a dry basis in its overview of diets for diabetic dogs.