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The price on the shelf is the wrong number. A bag priced at twice the rate per pound can be cheaper to feed if it carries more calories per pound, and a cheap bag can be the expensive one. The label gives you everything you need to settle it.
Step 1: find the calorie content
AAFCO requires a calorie content statement on pet food labels, expressed as kcal per kilogram and also per familiar household measure such as a cup or a can. It appears under its own heading, separate from the guaranteed analysis.
Write that number down for each food you are comparing. This is the only figure on the bag that lets you compare like with like.
Step 2: work out your dog’s daily calories
The veterinary starting point is resting energy requirement, RER, multiplied by a factor for life stage and activity:
RER = 70 x (weight in kg) to the power 0.75
Ohio State’s veterinary nutrition service gives the worked example of a 10 kg adult neutered dog: RER of about 400 calories a day. Multiply by the appropriate factor for your dog, and adjust from body condition rather than trusting the arithmetic.
If your dog is at a healthy weight and stable, you already know the daily amount. Multiply that by the calories per cup on the bag and skip straight to step three.
Step 3: price it per thousand calories
The comparison that works:
Cost per 1,000 kcal = (price of bag / kilograms in bag) / (kcal per kg) x 1,000
Then a year of food is:
Annual cost = daily calories x 365 / 1,000 x cost per 1,000 kcal
Why size changes the total so much
Because calorie needs scale with the 0.75 power of body weight, not linearly. A 40 kg dog needs roughly 2.8 times the calories of a 10 kg dog, not four times. That still means a large dog costs several times more to feed over a lifetime, and it is the single largest recurring difference between owning a small dog and a large one.
The same exponent explains why treats matter more for small dogs. A biscuit that is two percent of a Labrador’s daily calories can be eight percent of a terrier’s.
Four ways to lower the number honestly
- Compare per thousand calories before switching brands. Sometimes the premium bag wins.
- Buy the size you will finish within about six weeks of opening. Fat goes rancid, and a stale bargain is not a bargain.
- Count treats into the daily total and subtract them from meals. This is a health measure that happens to save money.
- Do not switch foods for price alone if your dog is doing well on one that suits it. Digestive upset costs more than the saving.
The dog food label guide addresses nutritional adequacy before price comparison. The feeding amount guide connects a package with the quantity consumed.
Questions people ask
How do I compare two dog foods on price?
Convert both to cost per 1,000 calories using the kcal per kilogram printed on the label. Cost per pound is misleading because foods differ in calorie density.
Where is the calorie content on a dog food bag?
Under a heading called Calorie Content, separate from the guaranteed analysis. It gives kcal per kilogram and kcal per cup or can.
Is wet food more expensive than dry?
Per calorie, usually yes, because most of the can is water. Whether that matters depends on the dog: some dogs eat better on wet food, and hydration has its own value.
Does a big dog cost four times as much to feed as a small one?
Less than that. Calorie needs scale with weight to the power 0.75, so a 40 kg dog needs roughly 2.8 times the calories of a 10 kg dog.
Where these figures come from
- Calories Association of American Feed Control Officials · aafco.org
- Calorie Content Association of American Feed Control Officials · aafco.org
- Companion Animal Nutrition Support Service, basic calorie calculator Ohio State University Veterinary Medical Center · vmc.vet.osu.edu
Figures last checked September 2026.
