How much should you feed your dog? Based on calorie needs & food type
The right daily portion depends on your dog's calorie needs (calculated from their weight using the RER formula) and the caloric density of the food. The formula is:
Daily food (grams) = Daily kcal needed ÷ (food kcal per 100g) × 100
The tricky part is that different foods vary enormously in caloric density. Standard dry kibble is about 340–380 kcal/100g, high-energy kibble can be 420–500 kcal/100g, wet food is typically 80–110 kcal/100g (because it's 70–85% water), and raw food is around 120–180 kcal/100g.
The feeding guide on a dog food bag is a starting point, but it's usually an overestimate (since manufacturers benefit from you using more food). A more accurate method: calculate your dog's daily calorie need (RER × life-stage factor) and divide by the food's kcal content. Weigh food with kitchen scales for accuracy — measuring cups are unreliable because kibble density varies so much. Adjust over 2–4 weeks based on body condition score.
Adults: 2 meals per day (morning and evening) is ideal. Puppies under 3 months: 4 meals/day. Puppies 3–6 months: 3 meals/day. Puppies 6–12 months: 2–3 meals/day. Large and giant breeds benefit from 2–3 smaller meals to reduce the risk of bloat (gastric dilatation-volvulus or GDV), which can be life-threatening. Never let large dogs run or play vigorously within 1–2 hours of eating.
Cups are notoriously inaccurate for dog food because kibble density varies greatly. An 8 oz measuring cup typically holds 85–125 g of dry kibble depending on the kibble size and shape. To be accurate, use a kitchen scale and weigh in grams. Many modern pet food bags now include both cup and gram measurements — if grams are listed, always use them. A digital kitchen scale costs £5–15 and is one of the best investments for accurate pet feeding.
Wet food is typically 70–85% water, making it much less calorie-dense than dry food. A typical 400g can contains about 350–450 kcal (compare to ~1,400–1,600 kcal in 400g of dry kibble). Wet food is beneficial for dogs with urinary issues, dental problems, or picky eaters, but costs more per calorie and spoils quickly once opened. A mixed diet (part dry, part wet) balances cost with palatability and hydration benefits.
If your dog eats a complete and balanced commercial diet, extra supplements are usually not needed and can cause imbalances. Vitamin D toxicity from over-supplementation is a real risk. Exceptions: omega-3 fatty acids (EPA/DHA from fish oil at 20–55 mg/kg body weight) for skin/coat and anti-inflammatory benefits; glucosamine and chondroitin for senior dogs or those with joint disease; and B vitamins during periods of stress, illness, or poor appetite. Always consult your vet before adding supplements.