Dry vs Wet Pet Food, Explained
The key difference is water: canned food is about 75 to 78 percent moisture, dry food 10 to 12 percent, so compare dry matter and feed by calories.
By Jennifer HunterContributing writer.
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The short answer
Wet and dry pet food can both be a complete diet. What matters first is the label: the FDA says a food with "complete and balanced" in its nutritional adequacy statement is meant to be fed as the pet's only diet, while treats and supplements usually are not. After that, the big difference is water.
Wet vs dry dog food: the water gap
According to the FDA, canned pet food is typically 75 to 78 percent moisture, while dry food is typically 10 to 12 percent.
| Canned (wet) | Dry (kibble) | |
|---|---|---|
| Typical moisture | 75 to 78% | 10 to 12% |
| Calories per kilogram as fed | Lower, because of the water | Higher |
| After opening | Refrigerate or throw out leftovers | Keep cool, dry and sealed |
The guaranteed analysis is printed "as fed," water included, so a dry food can look higher in protein than a canned one when it is not.
How to compare protein fairly
The FDA's method converts each label to a dry matter basis:
- Subtract the moisture percentage from 100 to get the percent dry matter.
- Divide the nutrient's percentage by the percent dry matter.
- Multiply by 100.
The FDA's example (cat food): a canned food lists 12% protein and 78% moisture, so it has 22% dry matter and 12 / 22 x 100 = 54.5% protein on a dry matter basis. A dry food lists 37% protein and 12% moisture: 37 / 88 x 100 = 42%. The kibble looks richer on the label, but the canned food has more protein once the water is set aside.
How much dry food to feed a dog
Start with the feeding directions on the bag. AAFCO, which writes the model rules most states follow, says a complete and balanced food must state how much food to give per weight of animal per day for its life stage. It also calls those directions guidelines that may need adjusting.
Calories help you fine-tune. Under AAFCO's model rules, labels show a "Calorie Content" statement in kilocalories per kilogram and per familiar unit such as per cup or per can. If you mix wet and dry food, add the calories from both so the daily total stays in line. AAFCO suggests asking a vet how many calories your pet needs; age, weight and activity all change it.
How long dry food lasts once opened
The FDA does not give a fixed number of weeks. Its storage advice:
- Keep dry food in its original bag with the top folded down tightly, or put the whole bag inside a storage bin.
- Store it in a cool, dry place below 80 F; heat and moisture can break down nutrients.
- If you pour kibble into a bin, use a clean, dry one with a tight lid, wash it between bags, and save the lot number and "best by" date from the bag.
Use the bag's "best by" date as the outer limit, and follow any after-opening guidance printed by the maker.
How we count
Moisture ranges, the dry matter method and storage rules are the FDA's; feeding direction and calorie label rules are AAFCO's. All are linked under Sources. The protein example is the FDA's. Wiki Shopping lists 184 dry pet foods, a count from our database on October 26, 2026.
Shopping on Wiki Shopping
Dry food sits in the pet supplies department. Read each listing's bag size and life stage before you buy.