Dog & Cat Food Calculator
Find out how much to feed your dog or cat each day: calories, then grams, cups or cans of your own food. Advanced adds body condition, treats, meals and cost.
Puppies under 4 months need the most energy.
On a 5-point scale? Double it and take away 1 (so 3 becomes 5).
Look for “calorie content” or “metabolisable energy” on the bag. Most dry foods have 3,000–4,500 kcal/kg.
An 8 fl oz (250 ml) measuring cup of kibble is about 90–120 g. Weigh one for the best answer.
Keep treats at or under 10%. They’re taken off the main food.
Most adults: 2 meals. Puppies and kittens: 3–4.
Daily feeding chart by weight
Same life stage and food as above. The row nearest your pet is highlighted.
How your pet’s food is worked out
Your numbers, step by step, from resting energy to the bowl.
- 1
Resting energy
70 × 20^0.75
= 662 kcal - 2
× life stage
662 × 1.6
= 1,059 kcal - 3
Room for treats
Treats ≤ 106
Food = 1,059 kcal - 4
Into your food
1,059 ÷ 3.6/g
= 294 g a day
2.9 cups · 2 meals
Read more: the formula, a worked example, the life-stage factors and tips
Vets work out a pet’s food in calories first, then turn the calories into an amount of your food. The calories come from body weight and life stage. The amount comes from how many calories the food has, which is printed on the pack. Want your pet’s age in human years too? Try the dog & cat age calculator.
The formula
Resting energy (RER) = 70 × (weight in kg)^0.75 kcal a day
Daily calories = RER × life-stage factor
(weight loss or gain: RER at the ideal weight)
Food calories = daily calories − treat calories
Grams a day = food calories ÷ kcal per gram of the food
Cups a day = grams ÷ grams in one cup
Cans a day = grams ÷ can size
Ideal weight = weight ÷ (1 + 0.1 × (body condition score − 5))
kcal per gram is the pack figure in kcal/kg ÷ 1,000, or kcal/100 g ÷ 100. Packs that show kJ: divide by 4.184 to get kcal. When you feed both wet and dry, the food calories are split by the share you choose, and each part is worked out on its own.
Worked example
A neutered adult dog weighing 20 kg, fed a dry food with 3,600 kcal per kg (3.6 kcal per gram):
- Resting energy: 20^0.75 = 9.457, and 70 × 9.457 = 662 kcal.
- Daily calories: 662 × 1.6 = 1,059 kcal.
- Food: 1,059 ÷ 3.6 = 294 g a day, which is 2.9 cups at 100 g a cup, or 147 g in each of 2 meals.
- Treats: up to 10% of 1,059 = 106 kcal. If you give that much in treats, the food drops to 1,059 − 106 = 953 kcal, which is 953 ÷ 3.6 = 265 g a day.
Life-stage factors used
| Life stage | Dog | Cat |
|---|---|---|
| Neutered adult | 1.6 | 1.2 (range 1.2–1.4) |
| Intact adult | 1.8 | 1.4 (range 1.4–1.6) |
| Less active or gains weight easily | 1.4 (range 1.2–1.4) | 1 |
| Weight loss (at ideal weight) | 1 | 0.8 |
| Weight gain (at ideal weight) | 1.5 (range 1.2–1.8) | 1.8 |
| Puppy under 4 months / kitten | 3 | 2.5 |
| Puppy 4 months to adult | 2 | – |
| Senior | 1.4 (range 1.2–1.4) | 1.1 (range 1.1–1.6) |
| Working dog: light / moderate / heavy | 2 / 3 / 5 (heavy range 4–8) | – |
| Pregnant: early / late | 1.8 / 3 | 2 / 3 |
| Nursing: small / medium / large litter | 3 / 4.5 / 6 (range 2–6) | 2 / 4 / 6 (range 2–6) |
Sources: Merck Veterinary Manual, daily maintenance energy table, Pet Nutrition Alliance, calculating calories, AAHA 2021 nutrition and weight management guidelines and WSAVA global nutrition guidelines (body condition score and the 10% treat guide). Where a source gives a range, the value used is shown with the range. Nursing litters are split across the published range by litter size. Factors are starting points: many pets need 20% more or less.
Tips
- Weigh, don’t scoop. Cups vary a lot. A cheap kitchen scale makes feeding far more accurate.
- Watch the body, not just the number. You should feel the ribs easily under a thin layer of fat, and see a waist from above.
- Losing weight: about 1% of body weight a week is a common safe pace (AAHA suggests 1–2% for dogs and 0.5–2% for cats). Never starve a cat: going without food can make cats seriously ill.
- Changing food: mix the new food in over about a week to avoid upset tummies, and work out the amount again from the new pack’s calories.
Common questions
How much should I feed my dog a day?
Start from calories, not the scoop. A 20 kg neutered adult dog needs about 70 × 20^0.75 = 662 kcal at rest, times 1.6 = about 1,059 kcal a day. With a dry food of 3,600 kcal per kg that’s about 294 g a day, or 147 g in each of two meals. Weigh your dog every few weeks and adjust.
How many calories does a cat need a day?
A 4 kg neutered indoor cat needs about 70 × 4^0.75 = 198 kcal at rest, times 1.2 = about 238 kcal a day. That’s about 63 g of a dry food with 3,800 kcal per kg, or about 3.4 pouches of a wet food with 70 kcal each. Active or intact cats need more.
What is RER for dogs and cats?
RER is the resting energy requirement: the calories a pet burns lying still in a comfortable room. Vets work it out as 70 × body weight in kg to the power 0.75. Daily needs are then RER times a life-stage factor, such as 1.6 for a neutered adult dog or 1.2 for a neutered cat.
How many treats can I give my dog or cat?
Vets suggest treats make up no more than 10% of the day’s calories. For a dog needing 1,059 kcal a day that’s up to about 106 kcal of treats. Take the treat calories off the main food, so the total stays the same. Advanced mode does this for you.
How much should I feed a dog or cat to lose weight?
The usual starting point is RER at the pet’s ideal weight, not its current weight: 1.0 × RER for dogs and 0.8 × RER for cats. A safe pace is about 1% of body weight a week. Always plan weight loss with your vet, especially for cats, which can get ill if they eat too little.
Why is this different from the feeding guide on the bag?
Pack guides are averages for a typical active pet. Neutered, older or indoor pets often need less, and young or working pets need more. This calculator uses your pet’s weight, life stage and the food’s own calories. Treat any figure as a starting point and check your pet’s weight and shape every 2–4 weeks.
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