- The calculator gives the grams of kibble per day from age, weight, activity and the food’s calories.
- The calories of 34 common foods are already in the list; for any other, artificial intelligence reads them from a photo of the bag, or you type them in.
- The figure is a starting point: check it on the dog every two weeks.
How much should a dog eat? The calculator above tells you how many grams of kibble to give a dog each day, from a two-month-old puppy to a senior. It starts from the resting energy vets use, 70 times the weight in kilos raised to 0.75, and multiplies it by a factor that depends on age: 3 up to three months, 2 at six months, 1.6 to 1.8 in the adult. It then divides the result by the calories of the kibble. For 34 foods sold widely in Europe the calories are already in the list; any other can be typed in, worked out from the analytical constituents printed on the bag, or read from a photo of the bag. The figure you get is a starting point, to be checked on the dog every two weeks. A guide by the Del Piccolo Diavolo kennel, which has bred Staffordshire Bull Terriers in Ostellato (Ferrara, Italy) since 2013.
The formulas behind the calculation
- Resting energy = 70 × weight in kg0.75
- Energy per day = resting energy × age factor × activity factor
- Grams per day = energy per day ÷ (kcal per 100 g ÷ 100)
- Kcal from the bag, when not printed = 3.5 × protein + 8.5 × fat + 3.5 × carbohydrates, where carbohydrates = 100 − protein − fat − fibre − ash − moisture (moisture 10% if missing)
- Weight at each age = adult weight × share: 25% at 2 months, 38% at 3, 50% at 4, 62% at 5, 72% at 6, 80% at 7, 86% at 8, 90% at 9, 93% at 10, 96% at 11, 98% at 12, for a medium-sized dog; growth ends around 10 months in small breeds, 15 in large and 20 in giant breeds
The sum has three steps. First the resting energy, what the dog needs at rest: 70 × weight in kg0.75. Then it is multiplied by the age factor and by the activity factor. Finally it is divided by the calories of the kibble, given in kcal per 100 grams.
| Age | Factor |
|---|---|
| Up to 3 months | 3 |
| 3 to 6 months | goes down from 3 to 2 |
| 6 to 12 months | goes down from 2 to the adult one |
| Adult, not neutered | 1.8 |
| Adult, neutered | 1.6 |
| Senior, from 8 years | 1.4 |
Activity moves the result like this: calm × 0.85, normal × 1, very active × 1.25, working or sport × 1.6. Up to four months activity counts for little, because almost all the energy goes into growth.
An example. An adult dog of 15 kg, normal activity, not neutered: 70 × 150.75 is about 533 kcal; times 1.8 it becomes 960 kcal a day. With kibble at 390 kcal per 100 g that is about 245 grams a day.
For the table by age the calculator estimates the puppy's weight as a share of the adult weight: a quarter at two months, half at four, three quarters around six months, nearly all of it at one year. That is the growth of a medium-sized dog. Small breeds finish earlier, around ten months; large breeds grow until about fifteen months and giant breeds until twenty, and the calculator stretches the table accordingly.
The calories of the kibble, also from a photo of the bag with artificial intelligence
Calories are the figure most often missing. In Europe the bag must show the analytical constituents, not the energy, and many brands leave it out. The list below gives 34 common foods, in the medium-breed version, with figures collected in October 2026 from manufacturers' and shops' pages. Recipes change: if the bag shows a different number, the bag wins.
| Brand | Kibble | kcal per 100 g | Figure |
|---|---|---|---|
| Acana | Adult Dog Recipe | 351 | manufacturer |
| Acana | Puppy Recipe | 366 | worked out |
| Advance | Medium Puppy Protect chicken | 428 | manufacturer |
| Almo Nature Holistic | Medium Adult chicken and rice | 379 | manufacturer |
| Brit Care | Adult Medium Breed lamb and rice | 381 | manufacturer |
| Brit Care | Puppy lamb and rice | 400 | manufacturer |
| Eukanuba | Adult Medium Breed | 406 | manufacturer |
| Exclusion Mediterraneo | Adult Medium chicken | 373 | worked out |
| Exclusion Mediterraneo | Puppy Medium chicken | 389 | worked out |
| Farmina N&D Ancestral Grain | Adult Medium/Maxi chicken and pomegranate | 389 | manufacturer |
| Farmina N&D Ancestral Grain | Puppy Medium/Maxi chicken and pomegranate | 444 | manufacturer |
| Farmina N&D Pumpkin | Puppy Medium/Maxi lamb and pumpkin | 414 | manufacturer |
| Gemon | Medium Adult chicken and rice | 399 | manufacturer |
| Hill's Science Plan | Adult Medium chicken | 374 | worked out |
| Hill's Science Plan | Puppy Medium chicken | 385 | manufacturer |
| Josera | Festival | 382 | manufacturer |
| Josera | JosiDog Adult Sensitive | 374 | manufacturer |
| Josera | YoungStar | 373 | manufacturer |
| Monge | Medium Adult chicken | 400 | manufacturer |
| Monge | Medium Puppy & Junior chicken | 420 | manufacturer |
| Natural Trainer | Puppy & Junior Medium chicken | 380 | worked out |
| Orijen | Original | 394 | manufacturer |
| Orijen | Puppy | 400 | manufacturer |
| Purina One | Medium/Maxi Adult chicken | 365 | worked out |
| Purina Pro Plan | Medium Adult chicken | 390 | manufacturer |
| Purina Pro Plan | Medium Puppy chicken | 405 | manufacturer |
| Royal Canin | Medium Adult | 388 | manufacturer |
| Royal Canin | Medium Puppy | 410 | manufacturer |
| Royal Canin | Medium Sterilised | 340 | worked out |
| Schesir | Medium Puppy chicken | 387 | worked out |
| Special Dog Excellence | Maxi Adult chicken | 420 | manufacturer |
| Taste of the Wild | High Prairie Adult | 372 | manufacturer |
| Taste of the Wild | High Prairie Puppy | 366 | manufacturer |
| Wolf of Wilderness | Adult Oak Woods wild boar | 369 | manufacturer |
When the energy is not printed, it can be worked out from the five analytical constituents on the bag, with the modified Atwater formula used by the European guidelines:
kcal per 100 g = 3.5 × protein + 8.5 × fat + 3.5 × carbohydrates
carbohydrates = 100 − protein − fat − fibre − ash − moisture
An example: protein 25, fat 16, fibre 2.3, ash 6, moisture 8. Carbohydrates are 42.7, and 3.5 × 25 + 8.5 × 16 + 3.5 × 42.7 gives 373 kcal per 100 g. That is how the figures marked «worked out» in the list were calculated. With 📷 «Photograph the bag» an artificial intelligence reads the values from the photo; there is a daily limit, set to keep costs down: if it does not work, today's limit has been reached.
How many meals a day
Up to six months three meals a day, from six months two, and two stay for life. A single large meal a day is not advised in a deep-chested dog, because it raises the risk of stomach dilatation and torsion. The calculator suggests the right number for the age and splits the ration over the meals you choose.
Questions on how much a dog should eat
How many grams of kibble does a 10 kg dog need?
An adult dog of 10 kg, not neutered and with normal activity, needs about 710 kcal a day: 70 times 10 raised to 0.75 gives 394 kcal of resting energy, and times 1.8 that becomes 710. With kibble at 380 kcal per 100 grams that is about 185 grams a day, split into two meals. If the dog is neutered the factor drops to 1.6 and the ration to about 165 grams. With richer kibble, at 420 kcal, the same energy fits into 170 grams: that is why the figure has to be worked out on the food you actually use.
How much should a puppy eat compared with an adult dog?
Far more, in proportion to its weight. Up to three months a puppy uses about three times its resting energy, against 1.6 to 1.8 times for an adult, because almost all of it goes into growth. A medium-sized puppy weighing 5 kg at two and a half months eats as much as an adult dog of 10 kg. From three to six months the factor falls towards 2 and around one year it reaches the adult one; in large and giant breeds this takes longer, up to fifteen and twenty months. Meals change too: smaller and more frequent in the first months.
Are the portions printed on the kibble bag reliable?
They are a reasonable starting point, but the manufacturer has to print a portion that suits many different dogs, and usually gives a wide range for each weight. A neutered dog that lives indoors and has two walks a day tends to sit at the low end of the range or even below it. The trouble is that a small excess does not show at once: it builds up day after day, and under the muscle of a sturdy dog it goes unnoticed for a long time. That is why the ration is checked on the dog, with a hand on the ribs, every two weeks, and adjusted by 10% at a time.
What changes when you switch to another brand of kibble?
The ration has to be worked out again, because two foods can give very different energy for the same grams. In the calculator's list they range from 340 to 444 kcal per 100 grams: moving from the first to the second without changing the portion means giving about 30% more calories. Choose the new food in the calculator, read the new portion, and make the change over seven to ten days by mixing the two foods, as explained in the guide to a puppy's first feeding. After two weeks, check the dog's ribs and adjust by 10% if needed.
How does the artificial intelligence read the photo of the bag?
Tap «Photograph the bag · AI» and take a sharp photo of the back of the bag, where the analytical constituents are printed; if the text is split, two photos are fine. The photo is read by an artificial intelligence, Anthropic's Claude: if the bag states the energy, it takes that figure; otherwise it reads protein, fat, fibre, ash and moisture and works out the kcal with the modified Atwater formula explained above. If it finds no figures, it searches the web for the calories from the name of the food. The photo is not kept. Check the result before adding it to the list; there is a daily limit of readings, 3 per person, set to keep costs down.
Check the figure on the dog
No formula knows the dog in front of you. The ribs should be felt with a flat hand without pressing, and from above you should see a waist. If the ribs can no longer be felt, cut the ration by 10%; if they show, raise it by 10%. A puppy is weighed once a week, on the same scales.
Treats are part of the total: they should stay under 10% of the day's calories, and the easiest way is to use part of the ration for training.
A puppy's first feeding
How many meals a day, how to change food and what never to give.