As Fed vs Dry Matter Basis: Why We Show You the Numbers on the Bag

Pick up any bag of dog food and turn it over. The guaranteed analysis says something like 26% protein, 15% fat, 10% moisture. Now open a dog food review site, and the same food might be listed at 28.9% protein. Neither number is wrong. They are measured on two different bases, and which one you are looking at changes what the number means.

On In The Kibble, every protein, fat and starch figure you see on a food card is as fed. That is a deliberate choice, and this guide explains why. If a food is 40% starch as fed, then about 40% of the weight of every cup you pour into the bowl is starch. Not 40% of some imaginary, water-free version of the food. 40% of the actual kibble your dog eats.

Below: what as fed and dry matter basis actually mean, how to convert one to the other in ten seconds, when dry matter is the right tool (it sometimes is, and we use it too), and why, for comparing one bag of kibble with another, as fed is the more honest number.

The Short Answer

• As fed means the percentage of the food exactly as it comes out of the bag, water included. It is what the guaranteed analysis on every US bag is printed in.
• Dry matter basis means the percentage once the water has been mathematically removed. It is a calculation, not something printed on the bag.
• For kibble against kibble, the two give almost the same ranking. Across the 1,760 dry foods we index, 98% contain between 8% and 12% moisture.
• Dry matter is essential when you compare foods with very different water content, like kibble against canned food. We never compare across formats on our cards, so as fed tells you what you need to know.

What “As Fed” Means

As fed (sometimes written “as is” or “as sold”) describes the food in the state your dog eats it. If a 100 gram scoop of kibble contains 26 grams of protein, that kibble is 26% protein as fed. Water is part of that 100 grams, just as it is part of the bowl.

This is the basis US pet food regulations require on the label. The guaranteed analysis lists crude protein and crude fat as minimums and crude fiber and moisture as maximums, all as fed. Calories per cup and calories per kilogram on the bag are also as fed, and so is every feeding chart ever printed. When your dog eats two cups a day, those cups are as fed.

So an as fed figure answers the most practical question there is: of the food I am actually scooping, how much is protein, how much is fat, how much is starch?

What “Dry Matter Basis” Means

Dry matter basis (often shortened to DMB or DM) answers a different question: if you took every drop of water out of this food, what would the rest be made of?

Water carries no protein, no fat, no starch and no calories. It just dilutes everything else. A canned food that is 78% water can only be 22% anything else, so its as fed protein figure looks tiny next to kibble even when it is genuinely protein rich. Removing the water puts both foods on the same footing.

The important thing to understand is that dry matter is a calculated number. No bag prints it. A review site or a calculator works it out from the guaranteed analysis.

How To Convert As Fed To Dry Matter

The formula is simple:

Dry matter % = as fed % ÷ (100 − moisture %) × 100

Take a kibble printing 26% protein and 10% moisture. The food is 90% dry matter, so:

26 ÷ 90 × 100 = 28.9% protein on a dry matter basis.

Same food, same protein, a bigger looking number. Nothing about the kibble changed. The water was just taken out of the denominator.

Here is protein on both bases for a typical kibble and two real foods we review:

The canned row is a real food we review, a Blue Buffalo Homestyle recipe. At 10% protein as fed it looks thin beside kibble. On a dry matter basis it is 45.5%, far more protein than the kibble. This is exactly the comparison dry matter exists for.

Why We Show As Fed

Dry matter is a useful tool. It is just the wrong default for someone standing in a pet store aisle, or scrolling a product page, deciding between two bags of kibble. Here is our reasoning.

1. It is what goes into the bowl

Your dog does not eat dry matter. Your dog eats kibble, water and all. A cup of kibble typically weighs around 100 grams, though it varies with how dense the pieces are. If that food is 40% starch as fed, roughly 40 grams of that cup is starch. That is a figure you can picture, measure and act on. A dry matter figure describes a food that does not exist on your kitchen floor.

2. You can check it against the bag

Every as fed protein and fat figure on our site matches what is printed on the package. If something looks off, you can turn the bag over and see for yourself in five seconds, and if we have it wrong, you can tell us. A dry matter figure can only be checked by redoing the arithmetic. We would rather show you numbers you can hold us to.

3. For kibble, dry matter barely changes the ranking

This is the part most explanations skip. Dry matter matters when moisture varies a lot. Among kibble, it barely varies. Of the 1,760 dry foods in our index, the median moisture is 10%, and 98% sit between 8% and 12%.

Because every kibble loses about the same share of its weight when the water comes out, converting to dry matter mostly just makes every number bigger by about the same amount. When we rank all 1,760 kibbles by protein as fed and again by protein on a dry matter basis, the two lists agree almost perfectly (a rank correlation of 0.995). Of the 176 highest-protein kibbles as fed, 169 are also in the top 176 on a dry matter basis.

In other words, if Food A has more protein than Food B as fed, it almost always has more on a dry matter basis too. Switching bases changes the size of the numbers, not the answer.

4. Bigger numbers flatter the food

Across our kibble index, average protein is 27.0% as fed and 30.1% on a dry matter basis. Average starch is 37.4% as fed and 41.7% dry matter. Dry matter inflates everything, the good and the bad. A “30% protein” headline sounds better than “27%”, even though it is the same food.

Mixing the two bases is where shoppers get misled. Compare one food’s dry matter protein with another food’s as fed protein, which is easy to do when one website shows one and the bag shows the other, and you can be off by three or four points without realizing it. Showing the bag’s own basis everywhere removes that trap.

5. Dry matter adds an assumption you cannot see

Moisture on a bag is a maximum, not a measurement. A food guaranteeing “10% moisture max” might really be 8%. Every dry matter conversion divides by that maximum, so it builds a guess into the result. As fed figures skip that step and stay closer to what the manufacturer actually guarantees.

6. Calories and portions are as fed anyway

Calories per cup, cups per day and how long a bag lasts are all as fed. The feeding calculator on every product page works in as fed because a scoop is as fed (our guide to how many calories your dog needs explains the math). Keeping protein, fat and starch on the same basis means every figure on a page can be read together without converting anything in your head.

What Our “Starch” Figure Means

One more piece of honesty. Dog food labels in the US do not print carbohydrate or starch at all. The starch figure we show is an estimate: 100 minus protein, fat, fiber, moisture and an allowance for ash (minerals). Technically that is total carbohydrate, so it also includes sugars and some soluble fibers, and it can run a few points high. We explain the method in our guide to carbohydrates in dog food.

Because it is calculated from as fed inputs, the estimate is as fed too. So “40% starch” on a kibble card means about 40% of what you scoop is carbohydrate, mostly starch, by weight. The across-the-board average for kibble is around 37%.

When Dry Matter Is the Right Tool

We are not against dry matter. We use it, just where it earns its place.

• Comparing different formats. Kibble against canned, fresh, frozen or freeze-dried food is meaningless as fed, because the water content is wildly different. This is why we never mix formats on a card or in an average: dry food is compared with dry food, wet food with wet food.
• Soft and semi-moist kibble. About 20 of the dry foods we review are “soft bites” style kibbles running 18% to 33% moisture. A soft kibble at 30% starch as fed is 44% starch on a dry matter basis, because so much of its weight is water. If you are comparing one of these with a regular crunchy kibble, look at both bases. Every product page shows the moisture and a dry matter column for exactly this reason.
• Checking against nutrient standards. AAFCO, which sets the nutrient profiles US complete and balanced foods are formulated to, states its minimums on a dry matter basis: 18% protein and 5.5% fat for adult maintenance, 22.5% protein and 8.5% fat for growth and reproduction. To compare a label with those, convert to dry matter first.
• Our own analysis. Behind the scenes, the figures we use to rate a food are worked out on a dry matter basis, so foods of different moisture are judged fairly. You see as fed; the math underneath accounts for water.

If you prefer to see dry matter, you can. Every brand comparison has an as fed / dry matter switch above the table, the reviews list lets you filter and sort protein and starch on either basis, and each product page has a full dry matter breakdown.

A Third Basis: Per 1,000 Calories

Veterinary nutritionists often go one step further and express nutrients per 1,000 kilocalories, the caloric basis. It answers “how much protein does my dog get for each unit of energy?”, which matters most when two foods have very different calorie density and the dog eats to its energy needs. It is the most precise way to compare, and also the least intuitive. For choosing between bags of kibble with similar calories per cup, as fed and dry matter tell the same story.

How To Read Any Label, Step by Step

1. Check the format. Only compare kibble with kibble, and canned with canned, as fed. Across formats, convert to dry matter first.
2. Check moisture. If both foods are between 8% and 12%, as fed comparisons are fair. If one is a soft or semi-moist kibble, convert both.
3. Read protein and fat as printed. They are minimums, so the real figures are usually a little higher.
4. Estimate starch. 100 minus protein, fat, fiber and moisture, minus about 6 to 8 for ash. That is what our cards show for you.
5. Look at calories per cup. It tells you how much you will be scooping, which affects how much of everything else your dog actually gets.

Frequently Asked Questions

Is dry matter basis more accurate than as fed?

No. Both describe the same food. Dry matter is more useful for comparing foods with different water content. As fed is more useful for understanding what is in the bowl, and it is the basis printed on the label. Dry matter also depends on the moisture maximum, which is a guarantee rather than a measurement.

Why do some websites show higher protein numbers than the bag?

They are almost certainly showing dry matter basis. For a typical kibble, dry matter figures run about 11% higher than as fed (protein of 27% becomes about 30%). Neither is wrong, but make sure you are comparing like with like.

How do I calculate dry matter basis?

Divide the as fed percentage by (100 minus the moisture percentage), then multiply by 100. A food with 25% protein and 10% moisture is 25 ÷ 90 × 100 = 27.8% protein on a dry matter basis.

Does 40% starch as fed really mean 40% of each cup is starch?

By weight, yes, as an estimate. If a cup weighs 100 grams and the food is 40% starch as fed, about 40 grams is carbohydrate. Since US labels do not print starch, that figure is estimated from the guaranteed analysis and can be a few points off either way.

Should I use dry matter to compare kibble with wet food?

Yes, always. Wet food is usually about 78% water, so its as fed numbers look small. Converting both to dry matter is the only fair way to compare them.

Which basis does AAFCO use?

Labels must print the guaranteed analysis as fed. AAFCO’s nutrient profiles, the minimums a complete and balanced food must meet, are stated on a dry matter basis and per 1,000 kilocalories.

The Bottom Line

Dry matter is a lens for comparing foods that hold different amounts of water. As fed is the food itself. When you are choosing between two bags of kibble, they hold almost the same amount of water, so the lens adds little except bigger numbers. We show you the numbers that match the bag in your hand and the scoop in your dog’s bowl, and we keep dry matter one click away for the times it really matters.

Ready to put it to use? Browse our dog food reviews, where every kibble shows protein, starch and calories as fed, or pit two brands against each other in Brand vs Brand.