How Much to Feed a Dog: Calculating the Daily Amount Step by Step

The feeding chart on a bag of kibble is only a rough estimate for an average dog. A dog’s real daily ration comes from two steps: resting energy requirement, then a multiplier for age, activity, and health status. You can run through this on a calculator or by hand in a couple of minutes.

Step 1: resting energy requirement (RER)

RER (resting energy requirement) is the amount of energy a dog would burn if it did nothing but rest all day. It’s the physiological baseline that every other part of the calculation builds on. The standard formula:

RER (kcal/day) = 70 x (weight in kg)^0.75

Raising weight to the power of 0.75, so-called metabolic weight, reflects the fact that energy expenditure doesn’t scale linearly with body mass. A dog twice as heavy doesn’t need twice the energy, because the ratio of body surface area to volume shrinks as size increases.

Worked example

For a 15 kg (33 lb) dog: 15^0.75 ≈ 7.62. RER = 70 x 7.62 ≈ 533 kcal a day. That number alone doesn’t yet tell you how much to feed, it’s just the starting point for step 2.

Step 2: the MER factor for age, activity, and status

MER (maintenance energy requirement, or total energy need) comes from multiplying RER by the relevant factor:

MER (kcal/day) = RER x factor

Dog category	Factor
Puppy under 4 months	3.0
Puppy 4 to 12 months	2.0
Neutered adult, normal activity	1.6
Intact adult, normal activity	1.8
Low activity / prone to obesity	1.2-1.4
Working / sporting dog	2.0-5.0
Senior	1.4
Weight loss (calculated from target, not current, weight)	1.0
Final third of pregnancy	3.0
Nursing	4.0-8.0 (depending on litter size)

These factors are rough ranges drawn from veterinary nutrition guidance (WSAVA, FEDIAF), not exact figures for every individual dog. Only tracking body condition over time confirms actual need.

How to judge which activity factor applies

“Normal activity” for an adult dog means roughly 1 to 2 walks a day totalling 30 to 60 minutes, without regular sport-level exertion. A dog doing training, fetch, or running alongside a bike for more than an hour a day is closer to the working range, factor 2.0 and up. A dog that spends most of the day indoors with short walks falls into the low-activity category at 1.2 to 1.4, even if it’s a formally healthy adult. The 5.0 upper end of the working-dog range matches extreme exertion, sled or hunting dogs in full work, and is essentially never used for a pet at home.

Why weight loss is calculated from target weight

If a dog needs to lose weight, RER is calculated from the weight you’re aiming for, not the current, heavier weight. Otherwise the ration comes out higher than the goal calls for, and the dog won’t actually lose weight. A factor of 1.0 means feeding at roughly the resting energy level of the target weight, which for most dogs produces a gradual, safe loss.

Step 3: converting kcal to grams of food

The daily kcal target needs converting to grams using the specific food’s metabolizable energy (ME), printed on the label in kcal per 100 g:

daily ration (g) = MER (kcal) / ME of food (kcal/100 g) x 100

Foods vary widely in ME, typically 300 to 420 kcal/100 g, so the same calorie need translates into very different gram amounts depending on the food chosen. This step is why “how many grams a day” can’t be answered without knowing the specific product.

Three worked examples

Chihuahua, 5 kg (11 lb), adult, spayed, normal activity

• RER = 70 x 5^0.75 ≈ 70 x 3.34 ≈ 234 kcal
• MER = 234 x 1.6 ≈ 374 kcal/day
• With a food at 380 kcal/100 g: 374 / 380 x 100 ≈ 98 g a day, split across 2 to 3 meals

Mixed breed, 15 kg (33 lb), adult, intact, normal activity

• RER = 70 x 15^0.75 ≈ 70 x 7.62 ≈ 533 kcal
• MER = 533 x 1.8 ≈ 960 kcal/day
• With a food at 350 kcal/100 g: 960 / 350 x 100 ≈ 274 g a day, split across 2 meals

Labrador Retriever, 30 kg (66 lb), adult, neutered, normal activity

• RER = 70 x 30^0.75 ≈ 70 x 12.82 ≈ 897 kcal
• MER = 897 x 1.6 ≈ 1,436 kcal/day
• With a food at 370 kcal/100 g: 1,436 / 370 x 100 ≈ 388 g a day, split across 2 meals

All three calculations are a starting point, not the final word. Always fine-tune the real amount based on how weight and condition change over time, see the section on weighing below. For a quick calculation using your own dog’s food, try our food portions calculator; you can look up age and its related factor with our dog age calculator.

Why the chart on the bag differs from the calculation

Feeding charts on kibble bags often assume a higher activity factor than a typical pet dog actually has, because manufacturers would rather overestimate the ration than risk an energy deficit. The chart also doesn’t distinguish neutering, which lowers energy needs by roughly 20 to 30 percent, or actual exercise levels. That’s why so many dogs gain weight on the chart amount. Treat it as an upper estimate, not a binding instruction.

Treats: the 10 percent rule

Treats, chew sticks, and bits of food from the table should together make up no more than 10 percent of total daily calorie intake. The rest has to come from a complete food designed to deliver a balanced ratio of protein, fat, minerals, and vitamins in precise proportions. When treats exceed that share by much, they dilute the nutritional completeness of the whole diet, even if total calorie intake is on target.

In practice, for the mixed breed above with a 960 kcal daily need, that’s a maximum of 96 kcal from treats, roughly one small biscuit or a handful of dried meat, not a whole bag at once. If treats make up more than that during training, reduce the main ration by the same amount to keep total calories on target.

Combining foods

Plenty of owners combine dry kibble with canned food, raw meat, or a home-cooked topper. In that case, work out the total daily need in kcal (MER) first, then split it between the components based on their energy density, not their volume or weight. For example, for a dog needing 960 kcal a day, where canned food at 90 kcal/100 g is meant to make up 40 percent of the ration and kibble at 350 kcal/100 g the rest, that’s 384 kcal (about 427 g) from the canned food and 576 kcal (about 165 g) from the kibble. Without this conversion, a combined diet easily ends up delivering far more or less energy than the dog needs, because a volume split of “half and half” doesn’t mean a calorie split of “half and half.”

Weighing and adjusting the ration

Weigh an adult dog and assess condition every 2 weeks; weigh a growing puppy even more often. If weight drifts from plan by more than about 5 percent over two weeks, adjust the daily ration by 10 percent up or down, then reassess after another two weeks. This cycle is more reliable than a one-off calculation, because it accounts for a specific dog’s real metabolism.

Body condition score

Body condition score, on a 1 to 9 scale, is a quick visual and hands-on test:

• 1-3: underweight, ribs, spine, and pelvic bones visible without needing to feel for them
• 4-5: ideal, ribs easily felt under a thin layer of fat, waist visible from above
• 6-7: overweight, ribs palpable only with pressure, waist barely visible
• 8-9: obese, ribs not palpable, no waist, fat deposits on the body

Body condition score is a more reliable indicator than the number on the scale alone, since it accounts for an individual dog’s build. A study by Kealy and colleagues (2002), published in JAVMA, found that Labrador Retrievers kept lean throughout their lives lived, on median, almost 1.8 years longer than littermates prone to carrying extra weight. Managing the ration by body condition isn’t just cosmetic.

When a dog is still hungry on the correct ration

A calculated ration matches energy need, not the feeling of fullness, and for some dogs, Labradors with a keen interest in food are a classic example, a correctly calculated amount just doesn’t feel like enough, even though it’s energetically right. The fix isn’t to feed more than the calculated need, it’s to split the ration into more, smaller meals through the day, choose a food higher in fibre and protein that satisfies better, or serve part of the ration from a slow-feeder toy. Increasing the amount just because a dog “seems hungry” is the most common route to overweight.

How many times a day to feed

• Puppy under 4 months: 4 times a day
• Puppy 4 to 12 months: 3 times a day
• Adult dog: twice a day
• Senior: twice a day, or 3 smaller portions for sensitive digestion

One large daily meal isn’t recommended, especially for large, deep-chested breeds, because of the higher risk of stomach torsion. Splitting the ration into more meals also helps stabilize hunger and curbs overeating in dogs that tend to gulp their food.

The RER and MER calculation is a starting point, not the final answer. The right amount of food only gets dialled in by watching a specific dog’s condition, energy, and satisfaction over time.