There is a table on the back of the food bag. Dog, 20 kilos: 278 grams a day. It sounds precise, and most families follow it every day for years. But the table does not know your dog is neutered, prefers the sofa to running and gets a chew in the evening.
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For an ordinary 20-kilo dog, neutered and having two walks a day, that can easily mean around 50 grams too much food. Every day. Over a year, that adds up to a good 18 kilos of food, almost as much as the dog itself weighs. Nobody has done anything wrong. Nobody has simply checked the number on the bag.
Checking it is not difficult. You need your dog’s weight, an honest look at daily life and the energy content of the food. A calculator handles the rest, or our free food calculator.
Why the feeding table is only a starting point
Manufacturers must provide feeding recommendations, and they base them on an average dog. But there is no such dog. Two dogs of the same weight can use very different amounts of energy. After neutering, many dogs’ needs drop noticeably. A young, playful dog needs more than an older one that prefers sniffing to running. Treats, chews and lunchtime leftovers do not appear in any table.
The food itself matters too. Two dry foods can differ considerably in energy content. Change food but keep the same number of grams, and you suddenly feed more or less without realising. That is why we calculate energy in kilocalories rather than grams. The grams come right at the end.
Five steps to the daily allowance
Step 1: The right weight
Use the weight your dog would be at an ideal body condition. Your hands help you judge this: the ribs should not be visible, but should be easy to feel with light pressure. A waist is visible from above, and the abdomen rises towards the back when viewed from the side. Vets use a scale from 1 to 9. Scores 4 and 5 are ideal. If your dog is there, simply use the current weight.
If your dog is noticeably rounder or thinner, use the estimated ideal weight. A 20-kilo dog at score 7 is about a quarter overweight, giving an ideal weight of around 16 kilos. With marked excess weight or underweight, a vet appointment is a good first step.
Step 2: Metabolic body weight
A 40-kilo dog does not need twice as much food as a 20-kilo dog, but considerably less than double. Larger bodies use proportionally less energy. Nutritional guidelines therefore use metabolic body weight: body weight raised to the power of 0,75. On a phone calculator, use the power button, usually “x to the power of y”.
For our 20-kilo dog: 20 to the power of 0,75 gives 9,46.
Step 3: The factor
Now daily life comes into play. Multiply metabolic body weight by a number that fits your dog:
| Your dog’s lifestyle | Factor |
|---|---|
| gains weight easily | 90 |
| low activity or neutered: under one hour of exercise a day, mostly on a lead | 95 |
| moderately active: one to three hours a day, fairly calm | 110 |
| highly active: one to three hours a day with running, play and dog sports | 125 |
| working dog: three to six hours a day | 150 to 175 |
An honest assessment helps. Two hours outdoors is not two hours of exercise if an hour and a half is spent sniffing and standing still. If you are between two categories, choose the lower one. You can always adjust later, and giving more food is easier than cutting back.
Step 4: Daily needs in kilocalories
Metabolic body weight multiplied by the factor gives daily needs. For the moderately active 20-kilo dog, that is 9,46 times 110, or around 1.040 kilocalories a day. If the same dog is neutered and rather laid-back, use a factor of 95 to get around 898 kilocalories. That is a difference of almost 150 kilocalories, every day.
Step 5: From kilocalories to grams
Many packages state the energy in 100 grams of food, often called “metabolisable energy” or “ME”. Calculate: daily needs divided by kilocalories per 100 grams, multiplied by 100.
A dry food providing 374 kilocalories per 100 grams gives the moderately active dog 278 grams a day. Exactly the number on the bag. For the neutered, laid-back dog, however, it is only 240 grams. There are the almost 40 extra grams going into the bowl every day, before treats have even been counted.
Treats belong in the calculation
Vets recommend that treats provide no more than one tenth of daily energy. For the 20-kilo dog needing 1.040 kilocalories, that leaves 104 kilocalories for rewards and chews. Meals get the remaining 936 kilocalories, or 250 grams of our example food rather than 278. Give treats while keeping the full amount in the bowl, and you overfeed every day, however small each reward looks.
This adds up particularly quickly in families. Everyone gives a little and nobody knows what the others have given. A shared note on the fridge listing what the dog has already had today helps more than any good intention.
What if there are no calories on the packaging?
You can estimate energy from the analytical constituents: crude protein, crude fat, crude fibre, crude ash and moisture. The calculation is a little longer because it accounts for how much the dog actually digests. Our food calculator handles it for you; simply enter the values from the packaging.
Check the result on your dog
Every calculation provides a starting point rather than a guarantee. Breed, coat, weather and temperament shift requirements, and even healthy middle-aged dogs differ by more than a third. Every new allowance therefore needs a check after two weeks: feel the ribs, look at the waist and ideally weigh your dog too. If your dog gains unwanted weight, give about one tenth less. If your dog becomes too lean, give one tenth more. Check again after two to three weeks. After a few rounds, you have an amount that suits your dog rather than an average dog from a table.
Where the simple calculation ends
Puppies need a different calculation because they are growing, and excessively fast growth in large breeds can harm their bones. Pregnant and nursing dogs, dogs needing to lose excess weight and dogs with illnesses also need more than these five steps. Your vet should be involved and set the targets.
The food calculator is quicker
If you would rather not enter the steps yourself, our free food calculator works out daily needs, a treat budget and the amount of your food in grams in a minute. You can also have a clear summary emailed to you for printing or pinning on the fridge.
All the calculations: the book
These five steps come from our book “Hundeernährung und Futterplan” (book in German). It works through every feeding method for small, medium and large model dogs: dry food, wet food, raw feeding, home cooking and vegan diets. There are also dedicated chapters on puppies, older dogs, excess weight, allergies and other special cases, 15 worksheets to complete, and feeding plans for healthy adult dogs. Find out more on our books page or directly on Amazon.
If you would like your dog on the wall, you will find dog portraits in all styles or the gifts for dog people.
To go with it: the food bowl with your dog’s name, made from stainless steel with a decorative band.
To see which life stage your dog is in, try our dog age calculator.
Further reading
- An older dog, new rules: giving your senior their best years
- The first 30 days with a puppy: a plan for weeks 1 to 4
- Puppy checklist: essentials and the first 3 days
The links to our books are affiliate links. Buying through them supports us at no extra cost to you.
Sources: FEDIAF Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs, Publication September 2025 (energy requirements, body condition assessment); National Research Council (2006): Nutrient Requirements of Dogs and Cats (energy from analytical constituents). Accessed on 26.09.2026. The example calculations come from the book “Hundeernährung und Futterplan” by Print my Pet.
