Choosing a dog food is a decision with many inputs, and cost is only one of them. But cost is the one that can be worked out exactly, and many owners get it wrong by comparing the price on the front of the bag. A 14 kg bag at 38 looks cheaper than a 10 kg bag at 36, and in this example it is, but the reason is not what it seems. This guide takes three example foods through a full comparison: price per kg, energy per kg, cost per 1,000 kcal, grams per day and cost per day, with monthly and yearly totals, and then adds the factors that cost does not capture. The foods and prices are invented for the arithmetic; use your own. The method is the one behind the Pet Food Price per 1,000 kcal Calculator, and the background is in price per 1,000 kcal.
The three foods
| Food A | Food B | Food C | |
|---|---|---|---|
| Bag size | 14 kg | 10 kg | 12 kg |
| Bag price | 38.00 | 36.00 | 52.80 |
| Energy (kcal/kg) | 3,300 | 3,600 | 3,900 |
The dog is a neutered 20 kg adult needing 1.6 × 70 × 20^0.75 = 1,059 kcal a day.
Step 1: price per kg
| A | B | C | |
|---|---|---|---|
| Price per kg | 38.00 ÷ 14 = 2.71 | 36.00 ÷ 10 = 3.60 | 52.80 ÷ 12 = 4.40 |
On this basis, A is the cheapest and C is the dearest, by 62%.
Step 2: cost per 1,000 kcal
cost per 1,000 kcal = price per kg ÷ kcal per kg × 1,000
| A | B | C | |
|---|---|---|---|
| Working | 2.714 ÷ 3,300 × 1,000 | 3.60 ÷ 3,600 × 1,000 | 4.40 ÷ 3,900 × 1,000 |
| Cost per 1,000 kcal | 0.82 | 1.00 | 1.13 |
A is still the cheapest, but the gap to C has narrowed to 37%, because C has more energy per kilogram. Price per kg overstated the difference.
Step 3: grams and cost per day
| A | B | C | |
|---|---|---|---|
| Grams a day (1,059 kcal ÷ kcal per g) | 321 | 294 | 272 |
| Cost per day | 321 × 2.714 ÷ 1,000 = 0.87 | 294 × 3.60 ÷ 1,000 = 1.06 | 272 × 4.40 ÷ 1,000 = 1.20 |
| Per month (× 30.4) | 26.5 | 32.2 | 36.4 |
| Per year (× 365) | 318 | 386 | 437 |
| Days a bag lasts | 43.6 | 34.0 | 44.1 |
The yearly difference between A and C is 119, or 37%. A bag of food C lasts as long as a bag of A despite being a smaller bag, because it is denser in energy. The bag size and the price per kg together hide this.
When price per kg misleads
Suppose a fourth food, D, is priced at 3.00 per kg at 2,900 kcal/kg.
| D | |
|---|---|
| Price per kg | 3.00 |
| Cost per 1,000 kcal | 3.00 ÷ 2,900 × 1,000 = 1.03 |
| Grams a day | 1,059 ÷ 2.9 = 365 |
| Cost per day | 365 × 3.00 ÷ 1,000 = 1.10 |
D is cheaper than B per kilogram (3.00 against 3.60) but dearer per day (1.10 against 1.06). The price per kg is lower; the calorie content is lower still. That is the trap, and the reason to compare per 1,000 kcal.
What cost does not tell you
A cost comparison assumes the foods are equivalent. They are not, and the sums say nothing about:
- Completeness. Is the food complete and balanced for your dog’s life stage? Look for the adequacy statement; see how to read a dog food label.
- Information from the maker. WSAVA suggests asking about the maker’s nutrition expertise, quality control and testing.
- Your dog’s response. Weight, coat, stool and appetite on a food tell you something no label does.
- Your dog’s needs. Puppies, seniors and dogs with health conditions need foods chosen with a vet.
- Availability and storage. A food you cannot buy reliably is not a good plan.
A more expensive food is not necessarily better, and a cheaper food is not necessarily worse. The cost sum shows what each costs; the other points decide whether it is the right food. For a protein comparison on a dry matter basis, see dry matter basis explained.
A scorecard
Put the numbers and the notes in one table, and score each food on the points that matter to you.
| Item | A | B | C |
|---|---|---|---|
| Cost per 1,000 kcal | 0.82 | 1.00 | 1.13 |
| Cost per day | 0.87 | 1.06 | 1.20 |
| Complete and balanced for life stage? | |||
| Maker answered questions? | |||
| Dog’s weight stable? | |||
| Dog’s stool and coat OK? | |||
| Easy to buy? | |||
| Notes |
Fill in the empty cells from the packs, the makers and what you see in your dog. The costs are the easy part.
A worked example
Keiko is choosing between her current food (B) and a cheaper one (A). Her dog is 20 kg.
| Step | Working | Result |
|---|---|---|
| Saving per day | 1.06 − 0.87 | 0.19 |
| Saving per year | 0.19 × 365 | 69 |
| Extra grams of A | 321 − 294 | 27 g a day |
| Weigh the dog monthly | for 3 months | |
| Switch gradually | over 7 to 10 days | as in the switch guide |
Keiko emails food A’s maker about its adequacy statement and testing, checks that the label says it is complete and balanced for adult maintenance, and switches gradually over a week and a half (see how to switch dog food). Her dog’s weight stays steady. The saving is 69 a year; she decides it is worth having, and notes that she will check again if the price changes.
Protein per 1,000 kcal and per unit of cost
Cost per calorie is only one comparison. If the labels list protein, you can compare protein per 1,000 kcal and the price of protein. Suppose the three foods list 24%, 26% and 28% crude protein.
| A | B | C | |
|---|---|---|---|
| Crude protein | 24% | 26% | 28% |
| Protein per kg of food | 240 g | 260 g | 280 g |
| Protein per 1,000 kcal | 240 ÷ 3,300 × 1,000 = 72.7 g | 260 ÷ 3,600 × 1,000 = 72.2 g | 280 ÷ 3,900 × 1,000 = 71.8 g |
| Price per kg of protein | 2.714 ÷ 0.24 = 11.31 | 3.60 ÷ 0.26 = 13.85 | 4.40 ÷ 0.28 = 15.71 |
Per 1,000 kcal the three foods carry almost the same amount of protein (about 72 g), though the percentage on the bag rises from 24% to 28%, because the richer foods have more energy too. The percentage on the bag looked like a difference, and per calorie it is not. This is why comparisons need the same base; see dry matter basis explained for the moisture side. Protein quantity also says nothing about quality or digestibility, which depend on the ingredients. The example foods are invented, and real labels will differ.
Using the comparison
Use the numbers to narrow a choice and then check the rest. A food that is 20% cheaper per day but not complete for your dog’s life stage is not an option, and a food your dog does well on may be worth a premium. The point of the sum is to make sure that whatever you pay, you pay it knowingly.
Recheck when prices move
A comparison is only true on the day it is made. Repeat the cost per 1,000 kcal when a price changes, because a promotion can change the ranking.
Common mistakes
- Comparing price per kg.
- Comparing bags of different sizes without converting.
- Ignoring energy density.
- Treating cost as the only factor.
- Not checking completeness.
- Switching suddenly.
- Not rechecking after a price change.
Quick summary
- Cost per 1,000 kcal = price per kg ÷ kcal per kg × 1,000.
- For a 20 kg dog (1,059 kcal a day): A 0.87, B 1.06, C 1.20 per day.
- The cheapest per kg can cost more per day than a dearer-looking food.
- Cost does not show completeness, the maker’s quality or how your dog does on it.
- Switch gradually and weigh the dog.
- Use the Pet Food Price per 1,000 kcal Calculator.
Frequently asked questions
How do I compare dog foods fairly?
Use cost per 1,000 kcal, then multiply by your dog's daily energy in thousands of kcal to get cost per day.
Is the cheapest bag per kg the cheapest food?
Not always. A food with fewer calories per kg needs more grams, so the cost per day can be higher than the price per kg suggests.
What else should I compare?
Whether the food is complete and balanced for your dog's life stage, the quality of the maker's information and how your dog does on it. Your vet can advise.
Where do I find kcal per kg?
On the pack or the maker's website, or estimate it from the analysis with modified Atwater factors.
Should I compare on a dry matter basis?
For nutrients such as protein, yes, especially when comparing wet and dry foods. For cost, kcal is the right base.
How often should I recheck?
When prices change, when you change food and when your dog's weight changes.
Sources
- NRC (2006) Nutrient Requirements of Dogs and Cats, National Academies Press: RER = 70 × kg^0.75; neutered adult factor 1.6
- WSAVA Global Nutrition Guidelines (selecting a pet food: complete and balanced statement, maker information)
- Pure arithmetic: cost per 1,000 kcal = price per kg ÷ kcal per kg × 1,000; cost per day = daily kcal × cost per 1,000 kcal ÷ 1,000
Related calculators
- Pet Food Price per 1,000 kcal CalculatorCompare two foods fairly by price per 1,000 calories instead of price per bag.
- Dog Food Cost CalculatorSee what it costs per day, month and year to feed your dog, from its calorie need and the price of the bag.
- Dog Food Calorie CalculatorWork out how many calories are in a dog or cat food from the nutrient percentages (guaranteed analysis) on its label, when no kcal figure is printed.
Keep reading
- Price per 1,000 kcal: Compare Pet Food FairlyWhy price per 1,000 kcal is the fair way to compare pet foods: the formula, worked dog and cat examples across dry, wet and premium foods, and cost per day.
- Dog Food Cost per Day by WeightDog food cost per day from weight: daily kcal ÷ kcal per gram × price per kg, with a table for 5 to 40 kg dogs at three prices, plus monthly and yearly totals.
- How to Read a Dog Food Label: kcal and AnalysisHow to read a dog food label: the adequacy statement, kcal per kg or cup, guaranteed analysis versus dry matter, ingredient order and a step-by-step comparison.
- Pet Sitter vs Boarding: Cost ComparisonHow to compare boarding, drop-in visits and an overnight sitter: rate × nights, a 3 to 14 night table, extras, break-even rates and what price cannot tell you.