Sussex Spaniel Ideal Weight and Diet

Adult standard 15.9 kg–20.4 kg (35 lb–45 lb). A neutered adult in the middle of that range needs about 985 kcal a day. Medium breed, Sporting group, typically 13–15 years.

Feeding a Sussex Spaniel

985 kcal a day

Cups a day: 2.6
Per meal (×2): 492 kcal
Resting need: 616 kcal
Breed standard: 15.9–20.4 kg

15.9 kg within the breed standard 20.4 kg

Daily calories by life stage

Daily calorie needs for a Sussex Spaniel by life stage
Life stage	Factor	Per day	Cups
Neutered adult	×1.6	985 kcal	2.6
Intact adult	×1.8	1,108 kcal	2.9
Obesity-prone	×1.4	862 kcal	2.3
Weight loss	×1.0	616 kcal	1.6
Puppy under 4 months	×3.0	1,847 kcal	4.9
Puppy 4-12 months	×2.0	1,231 kcal	3.2

This is a starting point, not a prescription. Breed standards are ranges and calorie formulas are estimates that a vet refines by watching the animal. Talk to your veterinarian before changing a diet, and especially before starting a weight-loss plan — sudden weight change can itself be a symptom worth investigating.

What the standard actually says

The AKC standard for the Sussex Spaniel gives an adult weight of 15.9 kg–20.4 kg and a height of 33–38 cm (13–15 in) at the shoulder. That spread is not sloppiness — it covers the difference between a small female and a large male of the same breed, and both are correct.

Calories follow weight, but not in a straight line. Energy need scales with bodyweight to the power of 0.75, not to the power of one. A dog at the top of this range needs 21% more food than one at the bottom, even though it weighs 28% more. That is why feeding by eye across two dogs of the same breed goes wrong so easily.

Neutering matters more than most owners expect. The same Sussex Spaniel needs about 1,108 kcal intact and 985 kcal neutered — roughly 11% less. Feeding the old amount after the operation is one of the commonest routes to a slowly overweight dog.

Across the breed's weight range

Sussex Spaniel calorie needs across the breed standard
Point in range	Weight	Pounds	Resting need	Neutered adult
Bottom of standard	15.9 kg	35 lb	557 kcal	892 kcal
Middle of standard	18.1 kg	40 lb	616 kcal	985 kcal
Top of standard	20.4 kg	45 lb	672 kcal	1,075 kcal

By life stage

Sussex Spaniel calorie needs by life stage
Life stage	Factor	Per day	Cups
Neutered adult	×1.6	985 kcal	2.6
Intact adult	×1.8	1,108 kcal	2.9
Obesity-prone	×1.4	862 kcal	2.3
Weight loss	×1.0	616 kcal	1.6
Puppy under 4 months	×3.0	1,847 kcal	4.9
Puppy 4-12 months	×2.0	1,231 kcal	3.2

At 18.1 kg, the middle of the standard. Cups assume 380 kcal per cup — check your own bag.

Frequently asked questions

How much should a Sussex Spaniel weigh?

The AKC breed standard puts an adult Sussex Spaniel between 15.9 kg and 20.4 kg — 35 lb to 45 lb. That is a range rather than a target: a dog at the bottom of it is not underweight and one at the top is not overweight. Frame, sex and body condition all move the right figure for an individual dog, which is why vets judge body condition score rather than the scales alone.

How many calories does a Sussex Spaniel need a day?

A neutered adult at the middle of the standard (18.1 kg) needs roughly 985 kcal a day — about 2.6 cups of typical dry food at 380 kcal per cup. An intact dog of the same size needs closer to 1,108, and a puppy under four months around 1,847.

How is the calorie figure worked out?

Resting Energy Requirement is 70 × bodyweight in kilograms to the power of 0.75, the standard allometric formula. That is then multiplied by a life-stage factor — 1.6 for a neutered adult, 1.8 intact, 3.0 for a puppy under four months. It is a starting point that a vet adjusts by watching how the dog responds, not a prescription.

How much should I feed a Sussex Spaniel to lose weight?

A weight-loss plan is fed to the target weight, not the current one — feeding maintenance calories for a body the dog already has is why diets stall. Select "weight loss" in the calculator and enter the target your vet agreed. Never start a weight-loss diet without that conversation: rapid loss is dangerous, and sudden weight change can itself be a symptom.

How long do Sussex Spaniels live?

The AKC gives a typical lifespan of 13–15 years for the Sussex Spaniel. Keeping a dog at a lean body condition through its life is one of the few things shown to extend it.

Breed standard: American Kennel Club breed standards. Energy formula: Merck Veterinary Manual, nutritional requirements of small animals.

Estimates for informational purposes only and not veterinary advice. Breed standards are ranges, not targets, and healthy weight varies with frame, age, neuter status and body condition score. Calorie formulas are a starting point that a vet adjusts by watching how the dog responds. Talk to your veterinarian before changing a diet, and especially before a weight-loss plan.