Calculator
How much food does my dog need?
Enter your dog's weight, age and activity along with the energy value from the bag. The calculator gives the daily amount in grams, the split into meals and the monthly usage.
On the bag this is the metabolisable energy (ME). If it is given per kg, divide by 10. If it is in kJ, divide by 4.184.
Daily portion
— g
— oz · range — g
Per meal
— g
2 meals a day
Energy
— kcal
resting need — kcal
Usage: — kg a month (a 12 kg bag lasts about — days)
Cost: — a month
Treat this as a starting point, not a verdict. Weigh your dog every two weeks and adjust by 10 % if the weight is moving the wrong way. Treats count towards the daily energy and should stay under 10 % of it.
How the calculator works
It starts from the resting energy requirement (RER), which veterinary nutrition calculates as 70 × (body weight in kg)0.75. For a 20 kg (44 lb) dog that comes to roughly 660 kcal a day. This formula is used by WSAVA and clinical nutrition textbooks and works better than a flat per kilogram figure, because small dogs burn considerably more per kilogram than large ones.
RER is then multiplied by a factor for life stage and activity to give the daily requirement, MER:
| Situation | Factor × RER |
|---|---|
| Puppy under 4 months | 3.0 |
| Puppy 4 to 12 months (large breeds to 18) | 2.0 |
| Adult, neutered, normal activity | 1.6 |
| Adult, intact, normal activity | 1.8 |
| Inactive or prone to weight gain | 1.2–1.4 |
| Active and working dogs | 2.0–5.0 |
| Senior | 1.4–1.6 |
| Weight loss | 1.0 (of ideal weight) |
The calculator applies activity as a multiplier of 0.8 to 1.5 on the base factor and cuts the portion by 20 % for an overweight dog. The daily amount in grams then follows from the food's energy: grams = MER ÷ (kcal per 100 g) × 100. That is why you need the figure from the bag; the gap between a light food and a performance food is easily 30 % in volume.
Where the calculation ends
Individual variation between dogs runs to about 25 % either way. Two dogs of the same breed and weight can need noticeably different amounts depending on metabolism, ambient temperature, coat and temperament. So treat the result as a starting point. The only reliable measure is the trend in weight and body condition: weigh your dog every two weeks and adjust by 10 % if the number is moving the wrong way. The calculator does not cover pregnancy, lactation or conditions that call for a prescription diet.
Body condition score
How to tell your dog is the right weight
The number on the scale is not enough, because the ideal weight varies by several kilos within one breed. Looking at your dog from above and feeling the ribs tells you more.
Too thin
BCS 1–3
- Ribs, spine and hip bones visible from a distance
- Sharp waist, tucked belly
- No fat cover and reduced muscle
Raise the portion by 10 % and ask your vet to rule out parasites or another cause.
Ideal
BCS 4–5
- Ribs easy to feel under a thin layer of fat
- Clear waist when seen from above
- Slight tuck of the belly from the side
Keep the portion and weigh every two to four weeks.
Overweight
BCS 6–9
- Ribs hard to feel through the fat, or not at all
- Waist gone, body oval from above
- Fat over the back and at the base of the tail
Cut the portion by 20 % and aim for 1 to 2 % of body weight lost per week.
The nine point scale is the standard vets work with and the one used in the WSAVA guidelines. Each point above five means roughly 10 to 15 % over the ideal weight.
Common questions
How much food should I give my dog per day?
It depends on weight, age, neutering, activity and the energy in the food. As a rough guide a 5 kg (11 lb) dog needs 90 to 120 g of standard kibble, a 10 kg (22 lb) dog 150 to 200 g, a 20 kg (44 lb) dog 250 to 330 g and a 30 kg (66 lb) dog 340 to 450 g a day. The calculator above works it out properly once you enter the kcal from the bag.
Why does the result differ from the feeding chart on the bag?
Manufacturer charts cover a wide range of dogs and tend to sit high, because they assume an intact, active dog. A neutered house dog on normal walks often needs 20 to 30 % less. A difference of 10 to 20 % is normal. What settles it is your dog’s weight trend and body condition.
What are RER and MER?
RER, the resting energy requirement, is what a dog burns at rest at room temperature. It is calculated as 70 times body weight in kilograms to the power of 0.75. MER, the maintenance energy requirement, is the daily need including movement, digestion and keeping warm, and comes from multiplying RER by a factor for life stage and activity.
Where do I find the energy value of the food?
On the bag, near the analytical constituents, look for metabolisable energy (ME), usually in kcal per 100 g or per kg. If it is given per kg, divide by 10. If it is in kJ, divide by 4.184. Standard adult kibble runs 340 to 390 kcal per 100 g, puppy and performance foods 400 to 450, and wet food 80 to 120.
How do treats fit in?
Treats should stay under 10 % of daily energy. The simplest approach is to take that share out of the measured daily ration and use it for training, or to use low calorie vegetables such as carrot or cucumber. Subtract calorie dense treats like dried meat or cheese from the day’s food.
How often should I feed my dog?
An adult dog twice a day, puppies under four months four times and up to six months three times. One large meal a day raises the risk of bloat in large breeds and makes hunger worse. Keep the times regular and do not leave the bowl down all day.