The maths, with your numbers
No guesswork and no brand chart. This is the same calculation a vet does on paper, so you can check it.
What this means for the bowl
Royal Canin X-Small Adult sits in the middle of the 140 dry dog foods we track, at 369 kcal per cup.
To show how much the food matters: a 40 lb spayed or neutered dog needs about 985 kcal a day. That is 2 ⅝ cups of this food, but 1 ⅞ cups of Purina Pro Plan All Ages Sport Performance 30/20 Salmon & Rice and 3 ⅝ cups of Kirkland Signature Healthy Weight Chicken and Vegetable. Same dog, same day, very different scoops.
A level 8 oz measuring cup holds about 96 g of this kibble. If you have kitchen scales, weighing is more accurate than scooping, because a heaped cup holds noticeably more than a level one.
Royal Canin X-Small Adult feeding chart
Daily amounts for healthy adult dogs with no treats, from the label calories and the AAHA 2021 energy factors. Split the amount into meals.
| Weight | Couch dog | Spayed or neutered | Very active |
|---|---|---|---|
| 5 lb 2.3 kg | ⅜ cup40 g | ½ cup54 g | ¾ cup67 g |
| 10 lb 4.5 kg | ¾ cup68 g | 1 cup91 g | 1 ⅛ cups113 g |
| 15 lb 6.8 kg | 1 cup92 g | 1 ¼ cups123 g | 1 ⅝ cups154 g |
| 20 lb 9.1 kg | 1 ¼ cups114 g | 1 ⅝ cups152 g | 2 cups191 g |
| 30 lb 13.6 kg | 1 ⅝ cups155 g | 2 ⅛ cups207 g | 2 ¾ cups258 g |
| 40 lb 18.1 kg | 2 cups192 g | 2 ⅝ cups256 g | 3 ⅜ cups321 g |
| 50 lb 22.7 kg | 2 ⅜ cups227 g | 3 ⅛ cups303 g | 4 cups379 g |
| 60 lb 27.2 kg | 2 ¾ cups261 g | 3 ⅝ cups348 g | 4 ½ cups434 g |
| 70 lb 31.8 kg | 3 cups293 g | 4 cups390 g | 5 ⅛ cups488 g |
| 80 lb 36.3 kg | 3 ⅜ cups323 g | 4 ½ cups431 g | 5 ⅝ cups539 g |
| 90 lb 40.8 kg | 3 ⅝ cups353 g | 4 ⅞ cups471 g | 6 ⅛ cups589 g |
| 100 lb 45.4 kg | 4 cups382 g | 5 ¼ cups510 g | 6 ⅝ cups637 g |
Label values: 369 kcal per cup, 3,840 kcal per kg. Source: royalcanin.com, checked 18 Oct 2026.
Questions
How much Royal Canin X-Small Adult should I feed a 50 lb dog?
About 3 ⅛ cups or 303 g a day for a spayed or neutered dog, before treats. That is 1,164 kcal a day divided by the food’s label value. Use the calculator above to adjust for your pet.
How many calories are in Royal Canin X-Small Adult?
The label states 369 kcal per cup, 3,840 kcal per kg (checked 18 Oct 2026). Recipes change, so check your bag.