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Pet BMI & Body Condition.

Five questions, scored the way a vet scores them — plus a BMI number if you want one.

Which pet?
How heavy are they?

Optional — used for the BMI number and the weight range below.

Use a baby scale if you can. For big dogs, weigh yourself holding them, then subtract your own weight.

Body condition

Answer all five to see the score

What the score means

The checklist maps onto the 9-point body condition scale vets use. Your answers are highlighted.

Note: this checklist is weighted towards picking up excess weight. It is not a test for an underweight pet — if your animal looks thin, has lost weight without a diet, or you can see individual bones, skip the score and see a vet.

About the BMI number

Pet BMI is a rough screen, not a diagnosis. Here is how it is worked out.

Step 1

Measure height

From the floor to the top of the shoulder blades — the withers. Stand the pet squarely against a wall and mark it.

Step 2

Measure weight

In kilograms (or convert: 1 lb = 0.4536 kg). Same scale, same time of day, every time.

Step 3

Height in metres, squared

Divide weight by height squared. A 10 kg dog standing 40 cm tall: 10 ÷ 0.4² = 62.5.

The cut-offs used here are 1.4 to 1.9 for dogs and 1.0 to 1.6 for cats. They are broad deliberately: a Dachshund and a Great Dane have completely different proportions, so the same number can mean different things. That is why the five-question score above matters more than the BMI figure.

Is My Pet Overweight?

That last line is the reason this page exists. Weight gain in pets is gradual — a few hundred grams a year — so the change is invisible when you see the animal every day. Vets see it instantly because they are comparing against the last visit, and against thousands of other animals.

Body condition scoring exists to close that gap. Instead of a single number on a scale, it asks you to feel and look at specific places, and it works across every breed and body type. A greyhound and a bulldog can both score a perfect 5 while weighing completely different amounts.

How to check your pet at home

You need thirty seconds and both hands. Do it standing over the animal, then crouch to their level for the side and front views.

1. Feel the ribs

Run your palms flat along both sides of the chest, pressing gently. On an ideal-weight pet the ribs feel like the back of your hand — you can find each one easily, but they are covered by a thin layer of padding, not sharp.

If you have to press to find them, there is fat over them. If they feel like your knuckles when you make a fist, the animal is too thin.

2. Look down from above

Stand over your pet while they stand up straight. There should be a visible waist — a dip behind the ribcage, wider at the chest, narrower at the hips. Viewed from above, an ideal pet looks a bit like an hourglass.

A straight line from ribs to hips means overweight. A bulge means obese.

3. Look from the side

The belly should tuck up from the bottom of the ribcage to the hind legs. In an ideal pet you can see a clear upward sweep.

A belly that hangs level with or below the chest is the classic sign. In cats, a small hanging pouch of skin is normal and does not count — what matters is fat over the ribs.

4. Check the tail base and spine

Run a finger along the spine and over the hip bones. You should feel bone under a thin covering. A fat pad over the tail base is one of the first places cats put on weight, and one of the last places it leaves.

Why it matters more than the number on the scale

Extra weight is not a cosmetic issue. It is mechanically and metabolically expensive:

  • Joints. Every extra pound on a dog is roughly four pounds of load through the knees and hips. Arthritis in an overweight dog is not just more painful — it is more painful because of the weight, and losing weight measurably reduces the pain.
  • Breathing. Fat around the chest and throat makes flat-faced breeds worse and can cause collapse in the heat.
  • Diabetes. Obesity is the single biggest risk factor for feline diabetes, and cats can go into remission when they lose weight.
  • Skin. Skin folds trap moisture and cause infections that are hard to clear while the folds remain.
  • Anaesthesia and surgery. Overweight patients are riskier to sedate and harder to operate on.
  • Lifespan. The best-known study on this followed Labradors for their whole lives: the dogs kept lean lived an average of around two years longer than the ones allowed to eat freely.

What to do if the score is too high

Weight loss in pets is simpler than in humans, mostly because you control every calorie they eat. The hard part is that everyone in the household has to agree.

  1. Weigh the food. Not a scoop — a kitchen scale, in grams. Most owners underestimate how much they are feeding by 20–30%.
  2. Measure the daily ration once, then set it aside each morning. Treats come out of that ration, not on top of it.
  3. Feed to the target weight, not the current weight. Use the food calculator and put in the weight you are aiming for, not today's weight.
  4. Stop free-feeding. Two measured meals a day. This is the single most effective change for most households.
  5. Make treats count. A carrot, a green bean or a single piece of kibble does the same emotional job as a biscuit.
  6. Add movement gently. For dogs, more walking. For cats, food puzzles and a wand toy — you cannot walk a cat, but you can make them work for dinner.
  7. Weigh monthly and log it. Aim for 1–2% of body weight per week in dogs, and no faster than that in cats.

If the score is high in a pet that is already on a measured diet, get a vet to check for thyroid problems and to rule out fluid retention, which can look like fat. And if the score is low, the same applies in reverse — unexplained weight loss is a symptom, not a goal.

General guidance based on the 9-point body condition system used in veterinary practice. Not a diagnosis. Pet BMI is a screening estimate — a vet assessment is the reliable answer.

Keep reading

Common questions

Is pet BMI actually accurate?

It is a rough screen, not a measurement. Pet BMI was adapted from the human formula and assumes a fairly standard body shape, which dogs and cats are not. A Dachshund and a Labrador can have the same BMI and completely different amounts of fat. Use the number as a starting point and the five-question score as the real answer.

My vet said my pet is a 7 out of 9. What does that mean?

A 4 or 5 out of 9 is ideal. A 6 is slightly over. A 7 means roughly 20% above ideal body weight, an 8 is about 30%, and a 9 is 40% or more. Vets use the same scale you are scoring with above — the questions map onto it directly.

How fast can my pet safely lose weight?

About 1–2% of body weight per week for dogs. Cats need the same pace or slower, and should never be crash-dieted — losing weight too quickly causes hepatic lipidosis, which is a serious liver condition. If your cat stops eating for more than a day while dieting, call a vet.

Is my cat's hanging belly fat?

Probably not. The loose pouch of skin on a cat's lower belly is called the primordial pouch, and it is normal anatomy that protects the organs and helps with running and stretching. It is not a sign of being overweight. What matters in cats is fat over the ribs and a fat pad at the tail base.

My pet is a healthy weight but still begs. What do I do?

Begging is usually about attention and routine, not hunger. Split the daily ration across more, smaller meals, use a food puzzle to stretch one meal over twenty minutes, and give attention instead of food when they ask. This is often the hardest part of a weight plan — and the one that decides whether it works.

Should I switch to a diet food?

Often the simpler fix is feeding less of the same complete food, which keeps the nutrient balance right. Purpose-made weight-management diets have their place, particularly for cats, who cannot safely lose weight on a very small volume of ordinary food. Ask your vet which fits your animal — and never put a growing puppy or kitten on a weight-loss diet without one.

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