Advanced options
A starting point, not a prescription: check your food's own feeding guide (kcal per 100g is on the pack), watch body condition over 2 to 3 weeks, and adjust. Treats count too. Ask your vet about puppies under 4 months, pregnant dogs, or any weight concerns.
What The Dog Food Calculator Works Out
- Daily calories: the veterinary Resting Energy Requirement (70 x bodyweight in kg to the power 0.75) multiplied by a life-stage factor: 1.6 for a typical neutered adult, 2.0 for active or working dogs, 1.4 for seniors and 3.0 for growing puppies. A 20kg adult comes out at around 1,000 to 1,100 kcal a day.
- Daily food amount: those calories divided by the food's energy density from the pack label. Dry foods run roughly 300 to 420 kcal per 100g and wet foods 70 to 120, which is why one brand's scoop chart does not transfer to another. At 350 kcal per 100g a 20kg dog needs about 300g a day.
- Per week: the daily grams times seven, in kilograms, for shopping and bag-size planning.
- Weight unit (advanced): enter the weight in pounds instead of kilograms; the card shows the kg conversion used.
- Neutered and body condition (advanced): entire adults burn more, so the factor rises by 0.2. For an overweight dog the calculator feeds 20% below maintenance for gradual loss; for an underweight dog 10% above. UK vet surveys consistently find around half of dogs overweight, so if in doubt feed to the lean side.
- Energy factor override (advanced): type any factor your vet has given you (for example 1.2 for a very inactive dog or 1.8 for a lean working breed) to replace the stage default.
- Meals per day and per meal (advanced): splits the daily ration evenly. Two meals suit most adults; puppies and giant breeds (bloat risk) often do better on three or four smaller ones.
- Treat allowance (advanced): sets aside a percentage of the daily calories for treats and dental chews and reduces the main-meal grams to match. Vets suggest treats stay under 10% of the daily budget.
- Food cost per month and bag life (advanced): enter the bag price and size to see the monthly and annual spend, the price per kg and how many days a bag lasts. A 12kg bag at GBP 45 feeding 300g a day lasts 40 days and costs about GBP 34 a month.
- Weight sensitivity table (advanced): the same calculation if the dog were 10% or 20% lighter or heavier, which shows how much a modest weight change alters the ration. Body condition is the real feedback loop: you should feel ribs easily under a light fat covering and see a waist from above. General guidance, not veterinary advice.
Source and further reading: PDSA pet health advice.