How Much to Feed a Dog: Weight, Calories and Portion Sizes

Adult dogs commonly eat 2 to 3 per cent of their body weight a day, but that is a starting point rather than a rule. The accurate method works from calories, which means reading how many kcal your food carries per cup or per 100 g. A 30 kg dog on a dense kibble may need 400 g a day, while the same dog on a lighter food needs 480 g.

Weigh the Dog, Then Convert to Calories

Weigh your dog rather than guessing. A bathroom scale works for most dogs: weigh yourself, then weigh yourself holding the dog, and subtract. Divide the daily total into two meals for an adult, or three to four meals for a puppy under 4 months.

Then turn weight into energy. Resting energy requirement is about 70 times the body weight in kilograms raised to the power of 0.75. For a 30 kg dog that comes to roughly 900 kcal a day before activity. Multiply by a life-stage factor to reach the daily target.

• Neutered adult, light exercise - about 1.6 times resting energy requirement
• Intact adult, moderate activity - about 1.8 times resting energy requirement
• Weight loss programme - feed about 1.0 times resting energy requirement, on vet advice
• Puppy under 4 months - roughly 2 to 3 times resting energy requirement, split across 3 or 4 meals
• Working sled dog, hard effort - 3 to 5 times resting energy requirement or more

Reading the Label: kcal per Cup and per 100 g

Every complete pet food carries a calorie statement, usually as kcal per kg, kcal per 100 g, kcal per cup or kcal per can. Find it on the back panel near the guaranteed analysis. Convert everything to one unit you can work with: 3,600 kcal per kg is 360 kcal per 100 g, which is about 320 kcal in a standard 8 oz measuring cup of kibble.

Then divide. A 30 kg dog needing 1,440 kcal a day on a 360 kcal per 100 g food eats 400 g. If the next bag lists 4,200 kcal per kg, the same dog gets 343 g. Two bags can look identical on the shelf and differ by 30 per cent in calories per scoop, which is how dogs end up overweight on a carefully measured portion.

A Worked Example for a 30 kg Dog

Thirty kilograms, neutered, two walks a day, weight steady. Resting energy requirement of 70 times 30 to the power 0.75 comes to about 900 kcal. Multiply by 1.6 for a neutered adult with light to moderate activity and the target is about 1,440 kcal a day.

At 360 kcal per 100 g that is 400 g of food, which works out at about 1.3 per cent of body weight. That sits below the 2 to 3 per cent guideline, which shows why the percentage shortcut overshoots on calorie-dense kibble. Serve it as two meals of 200 g and adjust from the dog's body condition after two weeks.

Push activity up and the number climbs fast. A working collie at four times resting requirement needs 3,600 kcal, which on the same food is a full kilogram a day, or roughly 3.3 per cent of body weight. Exercise level moves the portion far more than weight does.

Wet Food, Mixed Feeding and Treats

Wet food carries about 80 to 110 kcal per 100 g, roughly a quarter of the calories per gram in dry kibble. A 30 kg dog fed only wet food needs 1.4 to 1.8 kg of it a day, which is why most owners mix the two. When you mix, cost each part in calories and add them: 200 g of kibble at 360 kcal per 100 g supplies 720 kcal, leaving 720 kcal to come from the wet food.

Treats count toward the total. Keep them under 10 per cent of daily calories, so under 144 kcal for that 30 kg dog. A training treat is often 5 to 15 kcal, which allows a dozen across a day. Subtract those calories from the meals rather than adding them on top, and weigh treats rather than estimating by eye.

The Rib and Waist Check Beats the Scale

Breed size varies far too much for weight alone to tell you anything useful, so use your hands. Run them along the ribcage: you should feel each rib under a thin layer of fat without pressing hard. From above, look for a waist behind the ribs. From the side, the belly should tuck up toward the hind legs.

Score this on the 9-point body condition scale: 4 or 5 is ideal, 6 or 7 means cut portions by about 10 per cent, 8 or 9 means book a vet visit. Repeat the check monthly. A dog that gains 5 per cent of its body weight in a month is eating more than it burns, whatever the bag says.

Cost of Feeding a Large Dog

A 30 kg dog eating 400 g a day gets through about 12 kg of kibble a month, so a 15 kg bag lasts a little over four weeks. Monthly spending then tracks the price per kilo almost directly, which means a food costing twice as much per kilo costs twice as much to feed. Wet food, mixed feeding and a working diet all push the monthly figure up.

Cheaper foods often list fewer calories per cup, so you buy more kilos for the same energy. Compare cost per 1,000 kcal rather than cost per bag, because that is the only figure that lets two bags of different calorie density be judged fairly.