Dog Food Calculator
Enter your dog's weight, life stage, and the calories per cup on the bag. You get calories per day from the veterinary RER formula and the cups that works out to.
use ideal weight if your dog is overweight
typical dry food: 300-450 kcal/cup
Calories per day
1,076 kcal
RER 672 × 1.6
Cups per day
2.8 cups
at 380 kcal/cup · split across meals
Resting energy (RER)
672 kcal
70 × 20.4 kg^0.75
Worked example: 45 lb neutered adult
- 45 lb = 20.4 kg.
- RER = 70 × 20.4^0.75 = 672 kcal at rest.
- Neutered adult factor 1.6: 672 × 1.6 = 1076 kcal a day.
- At 380 kcal per cup: 1076 ÷ 380 = 2.8 cups, split into two meals of about 1.4 cups.
Daily calories by weight and life stage
| Weight | RER | Puppy, under 4 months× 3 | Puppy, 4 months to adult× 2 | Neutered adult× 1.6 | Intact adult× 1.8 | Weight loss× 1 | Working / very active× 2.5 | Senior, less active× 1.4 |
|---|---|---|---|---|---|---|---|---|
| 10 lb | 218 | 653 | 435 | 348 | 392 | 218 | 544 | 305 |
| 20 lb | 366 | 1098 | 732 | 585 | 659 | 366 | 915 | 512 |
| 30 lb | 496 | 1488 | 992 | 794 | 893 | 496 | 1240 | 694 |
| 45 lb | 672 | 2017 | 1344 | 1076 | 1210 | 672 | 1681 | 941 |
| 60 lb | 834 | 2502 | 1668 | 1335 | 1501 | 834 | 2085 | 1168 |
| 80 lb | 1035 | 3105 | 2070 | 1656 | 1863 | 1035 | 2587 | 1449 |
| 100 lb | 1223 | 3670 | 2447 | 1958 | 2202 | 1223 | 3059 | 1713 |
| 120 lb | 1403 | 4208 | 2806 | 2244 | 2525 | 1403 | 3507 | 1964 |
All figures in kcal per day. Divide by the kcal/cup on your bag for cups. The factors are the conventional veterinary ranges (WSAVA / Ohio State VMC); individual dogs vary by ±20%, so treat the result as a starting point and adjust to body condition over 3-4 weeks.
Adjusting after a month
- Ribs hard to find, waist gone: cut 10% and re-check in 3 weeks.
- Ribs and hip bones prominent, no fat cover: add 10%.
- Measure with a real cup. A coffee mug holds 1.3-1.5 measuring cups. Most "my dog eats exactly the chart" overfeeding is a mug problem.
- Recalculate after neutering (needs drop about 25%), when growth finishes, and every 10-15 lb of change.
Frequently Asked Questions
Why not just use the chart on the bag?
Bag charts are generic and usually generous -- they are written for intact, active adults, and most pet dogs are neutered and mostly asleep. The RER formula plus a life-stage factor is what veterinary nutritionists start from, and it typically lands 10-25% below the bag for a neutered house dog.
What is RER?
Resting energy requirement: the calories a dog burns at rest in a comfortable room, calculated as 70 × (body weight in kg)^0.75. The 0.75 exponent is why a 100 lb dog does not need ten times what a 10 lb dog needs -- metabolism scales with surface area more than mass.
My dog is overweight. Which weight do I enter?
The ideal weight, then choose the 'weight loss' factor. Feeding to current weight maintains it. Ask your vet for a target or use body condition: ribs easy to feel, visible waist from above. Aim for 1-2% of body weight lost per week and re-run the number every 5-10 lb.
How do I find calories per cup?
It is printed on every bag as 'kcal/cup' or 'kcal ME/cup', usually near the guaranteed analysis. Typical dry food is 300-450; puppy and performance foods run higher, weight-management foods lower. Wet food is labelled per can or per 100 g -- convert the daily calories the same way.
Do treats count?
Yes, and they add up: the guideline is that treats should be at most 10% of daily calories. A single dental chew can be 70-100 kcal -- for a 20 lb dog that is a fifth of the day. Subtract treats from the food amount rather than adding them on top.
These calculators use published veterinary formulas and are for general guidance. They are not a diagnosis and do not replace your veterinarian, who knows your animal's breed, history, and body condition.