How this dog weight loss calculator works
Three steps. First it works out a target weight, either the one your vet gave you or an estimate from your dog’s body condition score. Then it sets a daily calorie amount equal to the resting energy requirement (RER) at that target weight, which is how many vets start a weight-loss plan. Finally it shows a safe pace of loss, about 1 to 2% of body weight a week, and how long reaching the goal should take.
The formula is RER = 70 × (target weight in kg)0.75, with no extra multiplier. The gap between that and what your dog would normally eat is what drives the weight loss.
An example: Bruno is a 60 lb neutered Labrador with a body condition score of 7, so he’s roughly 20% over his ideal and should weigh about 50 lb. At his current weight he’d normally get about 1,335 kcal a day. His weight-loss target is about 725 kcal a day. Losing 10 lb at a safe pace should take somewhere between 8 and 17 weeks.
Find your dog’s body condition score
Vets judge weight by body shape, not just the scale, using a 9-point body condition score (BCS) where 4 to 5 is ideal. Run your hands along your dog’s sides and look from above and from the side:
| Score | What you see and feel | Roughly above ideal |
|---|---|---|
| 4–5 (ideal) | Ribs easy to feel under a thin layer of fat. A clear waist from above, and a tummy tuck from the side. | 0% |
| 6 | Ribs felt with a little pressure. Waist present but not obvious. | about 10% |
| 7 | Ribs hard to feel under fat. Waist barely visible. | about 20% |
| 8 | Ribs very hard to feel. No waist, fat over the lower back. | about 30% |
| 9 | Heavy fat over the chest, spine and base of the tail. Belly clearly bulges. | 40% or more |
The percentages are rough guides that fit standard definitions. Clinician’s Brief describes dogs 10 to 20% above ideal weight as overweight and those more than 20% above as obese. The British Veterinary Association treats a score of 8 or 9, or 30% above ideal, as obese. If you can, ask your vet to score your dog and set the target. It takes them seconds.
What about a dog BMI calculator?
BMI works poorly for dogs. A Greyhound and a Bulldog of the same height can have completely different healthy weights. That’s why vets use body condition scoring instead, and why this calculator starts from it.
Making the plan work
- Measure food by weight. A kitchen scale beats a scoop. Small overfeeds add up.
- Count every treat. Keep treats within 10% of the daily calories, or use part of the meal as treats.
- Weigh every two weeks. If your dog isn’t losing, cut about 10% and check again. If it’s losing faster than 2% a week, add a little food.
- Add movement gradually. Longer walks and play help, especially for joints, but food does most of the work.
- Consider a weight-loss diet. Prescription weight-loss foods keep protein and nutrients up while calories come down, so dogs feel fuller.
See your vet before starting. Weight gain can come from medical problems such as an underactive thyroid, and some conditions change what a safe diet looks like.
Why it matters
Extra weight puts strain on joints, makes breathing harder in hot weather and is linked to arthritis, diabetes and a shorter life. Even losing part of the excess usually helps with mobility and comfort quickly. Your dog doesn’t need to look skinny, just lean enough that you can feel the ribs easily.
Common questions
How fast should a dog lose weight?
About 1 to 2% of body weight a week. For a 60 lb dog, that’s roughly 0.6 to 1.2 lb a week. Faster loss can cost muscle and is harder to keep off.
How many calories should my dog eat to lose weight?
A common starting point is the resting energy requirement at the target weight, which is what this calculator shows. Your vet may adjust it.
What is my dog’s ideal weight?
For purebreds, breed standards give a rough range, but individual dogs vary. Body condition score is a better guide. Aim for a score of 4 to 5.
My dog is always hungry on a diet. What can I do?
Split food into more meals, use puzzle feeders, and swap some kibble for low-calorie vegetables like green beans. Higher-fiber weight-loss foods help too.
How do I turn calories into cups?
Use the link under the result. It opens the dog food calculator with your numbers filled in.
Sources
- Clinician’s Brief: Body condition score techniques for dogs
- BVA, BVNA, BVZS and BEVA: Policy position on obesity in dogs, cats, horses, donkeys and rabbits (PDF)
- Pet Nutrition Alliance: Calculating calories based on pet needs (PDF)
Last reviewed .