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.
A healthy adult Jack Russell Terrier weighs 11–13.2 lb (FCI breed standard No. 345 (Kennel Club standard gives no weight)). Below are daily amounts for that range, for a typical dry dog food (382 kcal per cup, the middle of the dog foods in our list). For your own food, use the calculator above: it is already set to a Jack Russell Terrier weight.
| Weight | Couch potato | Spayed or neutered | Very active |
|---|---|---|---|
| 11 lb 5.0 kg | ¾ cup77 g · 280 kcal | 1 cup102 g · 374 kcal | 1 ¼ cups128 g · 467 kcal |
| 13.2 lb 6.0 kg | ⅞ cup88 g · 322 kcal | 1 ⅛ cups117 g · 429 kcal | 1 ⅜ cups147 g · 536 kcal |
Daily totals with no treats. Worked out from resting energy (70 × kg0.75) and the AAHA 2021 life-stage factors. Weight source note: Not an AKC breed (AKC's closest is Russell Terrier). Kennel Club standard: weight proportionate to height (25-30 cm). FCI standard: 1 kg per 5 cm height, approx. 5 kg at 25 cm to 6 kg at 30 cm, converted to lb.