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The guaranteed analysis, and the conversion that makes it honest
What each guarantee means
If a label claims the food is "vitamin-enriched" or "contains minerals", the specific vitamins or minerals must also be guaranteed.
The dry matter conversion
FDA's method: subtract the moisture guarantee from 100 to get the dry matter percentage, then divide the nutrient's guarantee by that dry matter percentage and multiply by 100. FDA's published example compares three adult cat foods - the math is identical for dog food, which is why we reproduce it here.
| FDA's example (adult cat foods) | Canned #1 | Canned #2 | Dry food |
|---|---|---|---|
| Protein guarantee on the label | 12% | 11% | 37% |
| Moisture guarantee | 78% | 78% | 12% |
| Dry matter (100 - moisture) | 22% | 22% | 88% |
| Protein, dry matter basis | 54.5% | 50% | 42% |
All three in FDA's example clear the 26% dry-matter minimum for adult cat maintenance - but only after conversion can you see that the dry food has the lowest guaranteed protein of the three. Keep the limits in view: the conversion starts from a minimum protein guarantee and a maximum moisture guarantee, so it gives an estimate from the label guarantees on an equal-moisture basis, not a guaranteed dry-matter floor - it does not prove the exact protein content of any one bag, and real recipes can sit above their guarantees. Two products with the same moisture can be compared straight off the label; anything else needs the math. The label decoder does the conversion for you.
What the panel does not tell you
Guarantees are minimums and maximums, not exact contents, and they say nothing about ingredient quality or digestibility - a protein number does not say where the protein came from. For that, read the ingredient list alongside the panel, and check the adequacy statement for the life stage the food is meant for.