A typical neutered adult dog needs about 1.6 times its resting energy requirement per day, and resting energy is 70 times body weight in kilograms raised to the 0.75 power, so a 50 lb dog lands near 1,160 calories a day and a 20 lb dog near 590. The number on the back of the bag is a starting point, not a prescription, and most dogs need less than it says. Running the numbers yourself, instead of trusting whatever the bag suggests, takes five minutes. This guide gives you the formula, a table by weight, how to turn calories into grams of your food, how treats fit, and how to tell from the dog whether you got it right.
Why the bag is usually wrong for your dog
Feeding guides are written for a range of dogs and tend to sit at the generous end. Meanwhile the Association for Pet Obesity Prevention's 2022 survey classified 59 percent of US dogs as overweight or having obesity, with only 40 percent at an ideal body condition.1 Those two facts are related. The fix is to calculate a target, feed it by weight, and adjust to the dog in front of you.
The formula vets use
The Merck Veterinary Manual gives the resting energy requirement (RER) as 70 multiplied by body weight in kilograms raised to the 0.75 power. RER is what the dog burns lying around at a comfortable temperature. To get a daily maintenance target, Merck multiplies RER by a factor: 1.6 for a neutered adult, 1.8 for an intact adult, 1.4 for a dog prone to weight gain, 3 for a puppy under four months, and 2 for a puppy over four months.2
Ohio State's veterinary nutrition service uses the same RER and adds the caveat that matters most: individual dogs can vary by as much as 50 percent from the calculated value, so the number is a starting point for how much to feed, not an answer.3 A couch potato Basset and a working Border Collie of the same weight are not eating the same dinner.
Use ideal weight, not current weight, if your dog is carrying extra. Feeding to the weight the dog is now just maintains it.
Calorie table by weight
Calculated from the Merck formula and multipliers above. Round freely; the dog does not care about the last digit.
| Weight | RER (rest) | Weight prone x1.4 | Neutered adult x1.6 | Intact adult x1.8 | Active adult x2.0 |
|---|---|---|---|---|---|
| 10 lb (4.5 kg) | 218 | 305 | 350 | 390 | 435 |
| 20 lb (9.1 kg) | 366 | 510 | 585 | 660 | 730 |
| 30 lb (13.6 kg) | 496 | 695 | 795 | 895 | 990 |
| 40 lb (18.1 kg) | 615 | 860 | 985 | 1,110 | 1,230 |
| 50 lb (22.7 kg) | 727 | 1,020 | 1,165 | 1,310 | 1,455 |
| 60 lb (27.2 kg) | 834 | 1,170 | 1,335 | 1,500 | 1,670 |
| 70 lb (31.8 kg) | 936 | 1,310 | 1,500 | 1,685 | 1,875 |
| 80 lb (36.3 kg) | 1,035 | 1,450 | 1,655 | 1,865 | 2,070 |
| 90 lb (40.8 kg) | 1,131 | 1,585 | 1,810 | 2,035 | 2,260 |
| 100 lb (45.4 kg) | 1,223 | 1,715 | 1,960 | 2,200 | 2,445 |
The "active adult" column is my label for a 2.0 multiplier, which Merck lists for older puppies rather than for adults; I include it because a dog that runs trails daily or works will often need that much. The WSAVA calorie chart for healthy adult dogs, built on the 2006 NRC formulas, brackets the same range with 95 times kg to the 0.75 for inactive dogs and 130 for active ones, and it carries the same warning that dogs are individuals.4
Turning calories into food
Find the calorie content on the bag. It reads as kcal per kg and usually kcal per cup, near the guaranteed analysis. Divide your daily target by the kcal per cup to get cups per day, then split across meals. Better, divide by kcal per kg and multiply by 1,000 to get grams per day, and weigh it. VCA's weight reduction guidance recommends a kitchen gram scale over a measuring cup because cups are not accurate.5 A scale costs less than a bag of food and pays for itself in the first month.
Example: a neutered 50 lb dog, target about 1,165 kcal. Kibble at 3,800 kcal per kg means 1,165 divided by 3,800 equals 0.307 kg, or about 305 grams a day, about 150 grams per meal. Freeze dried raw at 4,500 kcal per kg is 260 grams a day, which looks like a very small scoop because the water is gone. That mismatch is why so many dogs gain weight after a switch to freeze dried; our rehydration guide covers how to portion it.
Treats count
The WSAVA Global Nutrition Committee's treat guide for owners is direct: "Treats should always make up less than 10% of a dog's daily calorie intake."6 For the 50 lb dog above that is about 115 kcal, which is two or three commercial biscuits or a small handful of freeze dried liver, not both. If you train with treats or the kids hand out chews, subtract that from the meals. Our training treats guide covers how to keep a heavy training day inside the budget.
How many meals
VCA's most common recommendation is at least two meals a day for adult dogs, and three or four for puppies, whose small stomachs cannot hold a full day's food at once.7 Two meals also gives you two chances a day to notice a dog who is off its food, which is one of the earliest signs something is wrong.
Check the dog, not the math
Weigh your dog every two weeks on the same scale, and run your hands over the ribs. The WSAVA body condition score chart describes an ideal 5 out of 9 as ribs palpable without excess fat covering, a waist visible behind the ribs from above, and an abdomen that tucks up when viewed from the side.8 If you have to press to find ribs, cut the daily amount by about 10 percent and recheck in two weeks. If ribs are sharp and the hips show, add 10 percent. Repeat until the dog holds steady at an ideal score. That loop beats any formula, including this one. If your dog is already carrying extra, our weight loss guide covers a safe rate and how to keep the dog from starving you out with the eyes.
Where the formula breaks down
Puppies, pregnant or nursing dogs, working dogs, and dogs with medical conditions all fall outside these multipliers, and a senior who has slowed down often needs noticeably less than a middle aged dog of the same weight. Very small and very large dogs sit at the edges where the formula is least reliable. If your dog is in one of those groups, the table gets you in the neighborhood and the body condition check does the rest. If you want a starting number for your specific dog, use the table above with the calories per cup printed on your bag, then adjust by body condition every two weeks.
When to call the vet
Call if your dog loses or gains weight without a change in food, since either can point to thyroid, kidney, or digestive problems rather than portions. Call if your dog seems ravenous all the time on a reasonable ration, or drinks and urinates far more than usual. Ask for a body condition score at every checkup and write it down; a slow drift from 5 to 7 is easy to miss at home.
Sources
- Association for Pet Obesity Prevention, "2022 State of U.S. Pet Obesity Report," 2022. petobesityprevention.org
- Merck Veterinary Manual, "Nutritional Requirements and Related Diseases of Small Animals." merckvetmanual.com
- The Ohio State University Veterinary Medical Center, "Companion Animal Nutrition Support Service: Basic Calorie Calculator." vmc.vet.osu.edu
- WSAVA Global Nutrition Committee, "Calorie Needs for Healthy Adult Dogs," 2020. wsava.org
- VCA Animal Hospitals, "Creating a Weight Reduction Plan for Dogs." vcahospitals.com
- WSAVA Global Nutrition Committee, "Feeding treats to your dog," 2025. wsava.org
- VCA Animal Hospitals, "Feeding Times and Frequency for Your Dog." vcahospitals.com
- WSAVA Global Nutrition Committee, "Body Condition Score chart, dogs," 2025. wsava.org