How Much Should A Cat Weigh?

How much should a cat weigh?

The average healthy adult cat should weigh between 3.8 kg (7.9 lbs) – 6 kg (13.2 lbs), however, the number on the scales is just a guideline. A body condition score is a more accurate assessment of a cat’s ideal weight as this takes into account the cat’s overall build and size.

This score ranges from 1 – 9. The World Small Animal Veterinary Association outlines the body condition score as follows:

  • 1 – Ribs are visible on shorthaired cats and there is no palpable fat. Lumbar vertebrae and ilia are easily palpated. Severe abdominal tuck.
  • 2 – Ribs are easily visible on shorthaired cats and there is no palpable fat. Lumbar vertebrae are obvious. There is a pronounced abdominal tuck.
  • 3 – Ribs are easily palpable and there is minimal palpable fat. Lumbar vertebrae are obvious. There is an obvious waist behind the ribs. Minimal abdominal fat.
  • 4 – Ribs are palpable with minimal fat covering. There is a noticeable waist behind the ribs and a slight abdominal tuck. The abdominal fat pad is absent.
  • 5 ideal weight – The cat is well proportioned, ribs have a slight fat covering and palpable and abdominal fat is minimal.
  • 6 – The ribs are palpable with a slight excess in the fat covering. Waist and abdominal fat pad are distinguishable but not obvious. There is no abdominal tuck.
  • 7 – The ribs are not obviously palpated, and there is a moderate fat covering. Waist is poorly discernable and there is an obvious rounding of the abdomen. There are fat deposits over the lumbar area.
  • 8 – Ribs are not palpable under a heavy layer of fat. Waist is absent. There is an obvious rounding of the abdomen and a prominent fat pad. There are fat deposits over the lumbar area.
  • 9 obese – Ribs are not palpable under a heavy layer of fat. There are fat deposits over the lumbar area, face and limbs. The abdomen is distended and there is no waist. There are extensive abdominal fat deposits.

Cats don’t vary in size as much as dogs do; however, there can be quite a difference between breeds of cat or even body type as well as gender. Some are small and muscular, long and lean or large and solid. Some of the larger breeds such as Maine Coons and Siberians can tip the scales beyond 6 kg and be well within a healthy weight.

How much should a cat weigh?

The following table is a guideline only, evaluating a cat’s body condition is a more accurate way to determine if a cat is overweight or underweight.

Small to medium cats or breeds3.5 to 5.5 kg (7.7 to 12.1 pounds)
Large cats or breeds6-8 kg (13 to 17.6 pounds)

Evaluating body condition

The number on the scales can give you a general picture of your cat’s weight, however as we know, cats come in all shapes and sizes and therefore instead of focusing entirely on a number on the scales, a better way to determine if your cat is overweight or underweight is to go by look and feel.

  • Ribs: You should be able to feel the ribs when you run your hands along your cat’s sides, but they should have a thin covering of fat over them. Ribs which can easily be seen or felt are an indicator your cat is underweight. If you can’t feel the ribs at all, he is overweight.
  • Spine: The same goes for the spine, you should be able to feel it when you run your fingers along the back, but it shouldn’t be overly noticeable. If you stand over your cat, you should see the torso tuck in where the ribs finish. An exaggerated tuck is a sign of an underweight cat; overweight cats may have no tuck at all.
  • Keep a record: Veterinarians usually routinely weigh cats during visits, it is a good idea to make a note of your cat’s weight when he is fit and well so that you can use this number to determine any weight gain or weight loss in the future. Make a file for your cat where all of his veterinary papers are stored and keep a note of his healthy weight in there.

Either way, you should see a veterinarian to determine if there is a medical reason your cat is underweight or overweight.

Causes of weight loss in cats

  • Inadequate amount of food – Underfeeding, inter-cat bullying or a deficient diet.
  • Hyperthyroidism – This endocrine disease is usually due to a benign tumour of the thyroid gland.
  • Diabetes mellitus – As glucose is unable to enter the cells, the body will become starved of energy, so it begins to break down fat stores as an alternative fuel source.
  • Kidney disorders such as acute or chronic kidney disease and glomerulonephritis
  • Addison’s disease – An endocrine disorder of the adrenal glands which results in a deficiency in the production of corticosteroids.
  • Cancer – Many types of cancer can lead to weight loss and wasting in cats.
  • Dental problems, which can make eating painful.
  • Pregnancy and lactation – Female cats need considerably more calories when they are pregnant or nursing a litter of kittens.
  • Intestinal parasites such as roundworm, cryptosporidium, giardia – Weight loss can occur if the parasite is competing with the cat for nutrients (in the case of roundworms), or by causing vomiting and diarrhea in cats.
  • Exocrine pancreatic insufficiency – A disease caused by a failure of the pancreas to secrete adequate levels of pancreatic enzymes which result in an inability to digest food.
  • Feline Immunodeficiency Virus – Viral infection, similar to HIV in humans.
  • Feline leukemia virus – FeLV is a viral infection caused by reovirus, which is in the same family as the feline immunodeficiency virus. It is an oncovirus, meaning it can cause cancer. It also suppresses the immune system.
  • Heartworm disease
  • Inflammatory bowel disease
  • Liver disease
  • Pancreatitis – An inflammation of the pancreas due to pancreatic enzymes which begin to break down and digest the organ.
  • Pyometra – Infection of the uterus.
  • Stress – Can lead to a loss of appetite.

Causes of weight gain in cats

  • Overfeeding
  • Acromegaly
  • Hypothyroidism
  • Pregnancy

How much should a cat eat?

The best way to calculate a cat’s daily requirements is to calculate your cat’s resting energy requirements (RER) which is the amount of energy (in calories) expended in a day without any activity; it is similar to basal metabolic requirements.

  • Growing kittens – RER x 2.5
  • Maintenance for a desexed adult cat – RER x 1.2
  • Maintenance for an entire adult cat – RER x 1.4
  • Obese prone – RER x 1
  • Weight loss – RER x 0.8

Related: How many calories should a cat eat per day?




Julia Wilson is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. She enjoys photography, gardening and running in her spare time. Full author bio Contact Julia