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Dog Food Calculator
Use this free dog food calculator to find how much your dog should eat each day. Enter your dog's weight, life stage and activity level, and get daily calories plus cups of food per day, based on the resting and maintenance energy formulas vets use as a starting point.
Weigh your dog, or ask your vet for the current weight.
Printed on the food bag, usually 300 to 450 kcal per cup.
How it works
The calculator works in three steps: resting energy, daily energy, and cups of food. First it works out your dog's resting energy requirement, or RER, which is the energy a dog burns in a day at rest. The formula is 70 times body weight in kilograms raised to the power 0.75. The power of 0.75 matters: energy needs grow more slowly than weight, so a 20 kg dog needs less than twice the food of a 10 kg dog.
Next it multiplies RER by a factor for life stage, then adjusts for activity, to get maintenance energy requirement, or MER — the calories your dog needs in a normal day. Puppies need the most relative to their size, because they are growing: a puppy under 4 months uses a factor of 3.0, and a puppy from 4 to 12 months uses 2.0. A neutered adult uses 1.6 and an intact adult 1.8, because intact dogs usually burn more. A senior dog uses 1.4. Activity then adjusts the result: low activity multiplies by 0.85, moderate by 1.0, and high activity by 1.15.
Finally it turns calories into cups. Divide the daily calories by the calories per cup of your food, which is printed on the bag, and you get cups per day. Then divide by the number of meals to get cups per meal. The default of 350 calories per cup suits many dry foods, but always enter your own food's number, because a dense food at 450 calories per cup needs far fewer cups than a light food at 300.
Enter weight in kilograms or pounds — the calculator converts pounds by dividing by 2.20462. Weigh your dog rather than guessing, and use the weight your vet would call ideal if your dog is overweight, not the current weight. Treats count too: keep them under 10 percent of daily calories, or the carefully measured meals will not add up to the right total.
Worked example
Milo is a 10 kg neutered adult dog with moderate activity. His owner feeds a dry food with 350 calories per cup and gives 2 meals a day. She enters 10 kg, Adult neutered, Moderate activity, 350 calories per cup, and 2 meals.
Step 1: Work out RER. 10^0.75 = 5.62, so RER = 70 × 5.62 = 394 calories a day at rest.
Step 2: Work out daily calories. The neutered adult factor is 1.6 and moderate activity is 1.0, so MER = 394 × 1.6 × 1.0 = 630 calories a day.
Step 3: Convert to cups. 630 ÷ 350 = 1.8 cups of food per day.
Step 4: Split into meals. 1.8 ÷ 2 = 0.9 cups per meal.
The tool shows the same result: 1.8 cups per day, 630 calories per day, 0.9 cups per meal across 2 meals. If Milo's owner switched to a food with 450 calories per cup, the same 630 calories would be only 1.4 cups a day — a useful reminder to check the bag every time the food changes.
FAQ
How much food should my dog eat per day?
It depends mainly on weight, life stage, and activity. A 10 kg neutered adult dog with moderate activity needs about 630 calories a day, which is about 1.8 cups of a food with 350 calories per cup. A puppy, an intact adult, or a very active dog needs more, and a less active or overweight dog needs less. Use the calculator with your dog's details, then check the amount against the feeding guide on your food bag.
What is RER in a dog food calculator?
RER is resting energy requirement: the calories a dog burns at rest in a day. It is calculated as 70 times body weight in kilograms raised to the power 0.75. Because energy needs grow more slowly than weight, a dog twice as heavy does not need twice the food. RER is the starting point, and the calculator multiplies it by a factor for life stage and activity to get daily calories.
How do I convert calories into cups of dog food?
Divide the daily calories by the calories per cup printed on your food bag. For example, 630 calories a day divided by 350 calories per cup gives 1.8 cups a day. Enter your own food's calories per cup in the calculator, because foods vary widely: a dense food may have 450 calories per cup, while a lighter food may have 300.
How many meals a day should I feed my dog?
Most adult dogs do well on two meals a day, morning and evening. Puppies under six months usually need three or four smaller meals, because their stomachs are small and their energy needs are high. Whatever the number of meals, split the daily amount evenly, and measure with a cup rather than guessing from the bag.
My dog is overweight. Should I just feed less?
Feeding less is part of it, but do it gradually and with a target in mind. Choose the less active option in this calculator, aim for slow weight loss of about 1 to 2 percent of body weight per month, and weigh your dog regularly. If your dog is very overweight, has a health condition, or takes medication, ask a vet for a feeding plan before cutting food sharply.