Flip over almost any bag or can of dog food and you’ll find a small box called the Guaranteed Analysis. It lists a few percentages: protein, fat, fiber, and moisture. Most people glance at it, see a number like “26% protein,” and move on.
That box is more useful than it looks, but only if you know what it does and doesn’t tell you. This guide walks through it in plain English, and shows a simple trick for comparing a wet food to a dry food without getting fooled by the water.
What the guaranteed analysis is
The guaranteed analysis is a required part of a pet food label. It gives minimums and maximums for a few basic nutrients. At a minimum, you’ll see:
- Crude protein (minimum)
- Crude fat (minimum)
- Crude fiber (maximum)
- Moisture (maximum)
Some foods list more, such as calcium, phosphorus, omega-3 fatty acids, or glucosamine. When a company makes a claim on the front of the bag (for example, “with omega-3s for skin and coat”), it is generally expected to back that up with a guarantee in this box.
If you’re new to labels, our How to Read a Dog Food Label guide covers the other sections, and Five Parts of a Dog Food Label Owners Often Overlook points out the parts people skip.
What “crude” means (it’s not an insult)
“Crude” refers to the lab method used to measure the nutrient, not the quality of the ingredients. Crude protein, for example, is estimated from the nitrogen in the food. It tells you how much protein is there, but not how digestible it is or where it came from.
Minimum and maximum are not exact amounts
This is the part most people miss. “Crude protein, minimum 26%” means the food has at least 26% protein. The real number could be 27% or 30%. “Moisture, maximum 10%” means it has no more than 10% water.
So the guaranteed analysis is a floor and a ceiling, not a precise recipe. It’s good for rough comparisons, not for counting grams.
What the guaranteed analysis does not tell you
- Ingredient quality. Two foods with 26% protein can use very different protein sources.
- Digestibility. How much your dog actually absorbs isn’t on the label.
- Whether the food is complete and balanced. That’s what the nutritional adequacy statement is for. See “All Life Stages” Dog Food: What It Really Means.
- Calories. Look for the separate calorie statement (kcal per kg and per cup or can) to see how energy-dense the food is.
The wet vs. dry problem
Here’s where people get tripped up. A typical dry kibble might say:
- Crude protein: 26% minimum
- Moisture: 10% maximum
A typical canned food might say:
- Crude protein: 8% minimum
- Moisture: 78% maximum
At first glance the kibble looks like it has more than three times the protein. But the canned food is mostly water. To compare them fairly, you have to take the water out of the math. That’s called the dry matter basis.
How to do dry matter math in three steps
- Find the dry matter. Subtract the moisture percentage from 100. That’s how much of the food is not water.
- Divide the nutrient by the dry matter. Take the protein (or fat, or fiber) percentage and divide it by the dry matter number.
- Multiply by 100. That gives you the percentage on a dry matter basis.
Example: the kibble
100 minus 10 moisture = 90% dry matter. Then 26 divided by 90 = 0.289. Multiply by 100 and you get about 28.9% protein on a dry matter basis.
Example: the canned food
100 minus 78 moisture = 22% dry matter. Then 8 divided by 22 = 0.364. Multiply by 100 and you get about 36.4% protein on a dry matter basis.
Once the water is out of the picture, the canned food actually has more protein per bite of real food than the kibble. Without the math, you’d have guessed the opposite.
| Food | Protein on label | Moisture | Dry matter | Protein, dry matter basis |
|---|---|---|---|---|
| Dry kibble (example) | 26% | 10% | 90% | about 28.9% |
| Canned food (example) | 8% | 78% | 22% | about 36.4% |
You can do the same thing for fat and fiber. A phone calculator is all you need.
When this comparison is useful
- Switching between wet and dry, or mixing them.
- Comparing toppers, fresh foods, or freeze-dried foods to kibble. These often have very different moisture levels.
- Following your vet’s guidance on fat or fiber. If your vet says “keep fat moderate,” dry matter numbers give you a fair way to compare options. Your vet may give you targets in a different form, so ask how they want you to compare.
A few cautions
- The numbers are still minimums and maximums. Dry matter math makes comparisons fairer, not exact.
- Higher protein isn’t automatically better. Puppies, seniors, and dogs with health conditions have different needs. Talk to your vet before chasing a number.
- Don’t forget calories. Two foods can look similar on protein and fat but differ a lot in calories per cup, which changes how much you feed.
- Change foods slowly. If the math convinces you to switch, mix the new food in over about a week. Our How to Change Dog Food Gradually guide has a simple schedule.
Quick checklist for the guaranteed analysis
- Find the four basics: protein, fat, fiber, moisture.
- Remember that protein and fat are minimums, and fiber and moisture are maximums.
- If you’re comparing foods with different moisture, convert to dry matter first.
- Check the calorie statement to see how much to feed.
- Check the nutritional adequacy statement to confirm the food fits your dog’s life stage.
Check the whole label, not just one box
The guaranteed analysis is one piece of the puzzle. Our free Dog Food Safety Check walks you through the label, the company, and recall history in a few minutes, so you know what’s really in the bowl.
Get the free Dog Food Safety Check
This article is general education, not veterinary advice. Ask your veterinarian about the right nutrient levels for your dog.