Pet food budgets: what changes the monthly number

The plain answer: your monthly food cost is the food's cost per day, times 30. Not the price of the bag. A cheap bag that your cat eats quickly can cost more per month than an expensive one that lasts. And you can work it out yourself from the label.

The two label numbers that matter

Every complete pet food sold in the U.S. carries information you can use for budgeting.

The nutritional adequacy statement

Look for a line referencing AAFCO — the Association of American Feed Control Officials. It tells you whether the food is "complete and balanced" for a life stage (growth, adult maintenance, or all life stages), or whether it's intended only for intermittent or supplemental feeding. A treat or topper that isn't complete can't be counted as a meal.

The calorie statement

The label must show calories, in kilocalories per kilogram and per a familiar unit such as a cup or a can. This is the key to the math. Two foods at the same price can contain very different amounts of energy per cup, which means your pet eats different amounts.

Doing the math

You need your pet's daily calorie target. The feeding chart on the bag is a starting point, but the better number comes from your veterinarian, who can account for weight, age, activity and whether your pet is spayed or neutered.

Then:

1. Calories in the package = kcal per cup (or can) × cups (or cans) in the package. For dry food, the bag lists weight; kcal per kg × bag weight in kg works too.
2. Days the package lasts = calories in the package ÷ daily calorie target.
3. Cost per day = package price ÷ days it lasts.
4. Monthly cost = cost per day × 30.

Example with made-up numbers

These figures are invented to show the arithmetic only — use your own label.

Step	Food A (example)	Food B (example)
Package price	40	55
Calories in package	12,000 kcal	18,000 kcal
Daily target	250 kcal	250 kcal
Days it lasts	48	72
Cost per day	0.83	0.76
Monthly (×30)	25.00	22.92

In this invented example, the pricier bag is cheaper per month because it's more calorie-dense. Your foods may land the other way. The point is to run the numbers.

What drives the number

For cats

• Wet vs dry. Wet food is mostly water, so you buy more weight for the same calories. Many cat owners feed some wet food for hydration and enjoyment; just know it moves the monthly line.
• Can size and waste. A large can that goes half-uneaten in the fridge costs more than its label suggests.
• Number of cats. Free-feeding several cats makes per-cat costs hard to track and can lead to overeating.
• Life stage. Kittens need growth food. The AAHA/AAFP Feline Life Stage Guidelines (2021) describe cats over 10 as senior, and diets often change around then.

For dogs

• Body weight. A large dog eats many times what a small dog eats. Size is the biggest driver of a dog's food bill.
• Activity. Working and very active dogs need more calories.
• Format. Fresh, refrigerated or freeze-dried foods usually cost more per calorie than dry kibble.

For both

• Prescription diets. Diets for kidney, urinary, digestive or allergy issues are prescribed by your vet and usually cost more. If one is recommended, ask whether there are equivalent options at different prices.
• Treats. Treats have calories and cost. If treats make up a meaningful part of the day, they belong in both the calorie count and the budget.
• Overfeeding. Extra calories cost twice: once at the store, again at the vet if weight becomes a health problem.

Ways to lower the monthly number

• Measure every meal with a real measuring cup or a kitchen scale.
• Buy larger packages only if you'll use them before they go stale; check the best-by date and store dry food sealed.
• Use autoship or subscribe-and-save if the per-unit price is genuinely lower — compare against the store.
• Don't switch abruptly to chase a sale. Sudden diet changes can upset stomachs, which can mean a vet visit that erases the savings. Ask your vet how to transition.

Food is one line in the bigger picture. See the first-year cost of adopting a cat or a dog for the rest.

Setting your budget line

Work out cost per day from your actual food and your pet's calorie target, multiply by 30, and add your usual monthly treats. Re-check whenever you change food, your pet's weight changes, or your vet adjusts the target.

General information only — your vet should set your pet's calorie target and any diet changes.