How this calculator works
It first estimates your dog's daily energy need with the veterinary RER method (70 × kg0.75, multiplied by a life-stage factor), then divides that by the energy density printed on your food's label.
Energy density varies a lot between foods, which is why "one cup, twice a day" advice is nearly meaningless. Typical ranges:
| Food type | Typical energy |
|---|---|
| Dry food (kibble) | 350–420 kcal / 100 g |
| Puppy & performance dry food | 400–450 kcal / 100 g |
| Wet food (cans, pouches) | 80–110 kcal / 100 g |
On EU packaging, look for "metabolisable energy" (ME) in the analytical section — often given in both kJ and kcal per 100 g. US brands typically state kcal per cup instead; the toggle above handles either.
Two practical tips that fix most portioning problems: weigh, don't scoop (volume scoops over-pour by 10–20% surprisingly consistently), and split the day's amount into two meals for adults, three to four smaller ones for puppies.
Frequently asked questions
How many grams a day for a 20 kg dog?
A typical 20 kg neutered adult needs about 1,060 kcal per day. On a 370 kcal/100 g dry food that's roughly 285 g daily — about 140 g per meal, twice a day. More or less active dogs can differ by ±20%.
The label shows kJ, not kcal. What do I enter?
Divide the kJ figure by 4.184. Example: 1,550 kJ/100 g ÷ 4.184 ≈ 370 kcal/100 g. Enter the kcal number with the kcal/100g toggle selected.
Why does my bag run out faster than the calculator says?
Almost always scoop drift or treats. Weigh portions with a kitchen scale for one week to recalibrate your scoop, and keep treats inside ~10% of daily calories — they're part of the budget too.