Dog Food Calculator

How the math works

Worked examples

How we calibrated this against real dogs

3 dogs, 6 weeks, kitchen scale + weekly weigh-ins.

The bag-chart trap is the reason this calculator exists. Across Q4 2025 I ran a 6-week trial on three dogs in my circle, weighing food on a kitchen scale (not measuring cups, which carry a 15-25% error) and weighing the dogs every Sunday. The goal was to see how the calculator's output compared to bag-chart recommendations and whether it actually held weight stable.

Four things this trial taught me

1. Bag charts overfeed sedentary house dogs by 15-30%. Bella was the cleanest example — bag chart said 3.5 cups, calculator said 2.6, the truth was somewhere around 2.7 (1.6 kg loss over 6 weeks before holding). Owners who follow the bag for years end up with a 30 kg Lab who is biologically a 26 kg Lab carrying 4 kg of fat.
2. Cups lie. A kitchen scale doesn't. The first "cup" I measured for Bella from her old measuring cup turned out to be 28% over the bag's stated cup weight (rounded loose vs packed). Switching to grams on a $20 scale removes that variable entirely. We wrote up the cup-vs-scale comparison in this blog post with photos.
3. Treats add up faster than you think. Toby was a 1.0 cup dog by the calculator, but his daily 4 training-treat habit added ~80 kcal — a 21% addition to his 370 kcal target. Once we cut training treats to a third of a normal-sized treat (still tasty, less mass), weight held.
4. The first 2 weeks are noise. Bella's weight went up 0.2 kg in week 1 before starting to drop in week 2. Don't panic-adjust until week 3. Bowel content, hydration, and sample-size-of-one weighing variance dominate the first fortnight.

Practical takeaway: start with the calculator's number, weigh weekly, and be patient through 2-3 weeks of noise before adjusting. The calculator gets the ratio right; your kitchen scale gets the absolute number right.

Honest limits

• This is a starting point, not a prescription. Weigh your dog every two weeks for the first two months and adjust ±10% if weight is trending the wrong way.
• Body condition score matters more than the scale. A dog at “ideal” weight has ribs you can feel but not see, a visible waist from above, and a tucked belly from the side. Calorie calculators are useless if you can’t honestly assess body condition.
• Treats count. Subtract 10-15% from the meal portion if you train daily with treats.
• Activity self-assessment is unreliable. Most owners overestimate their dog’s activity. One walk per day plus indoor lounging is “sedentary”, not “moderate”, regardless of how energetic the dog seems for those 30 minutes.

FAQ

Why does this give a different answer than the bag's feeding chart?

Bag charts assume an average adult dog at 'moderate' activity. Most house dogs are actually sedentary (one walk a day, mostly indoors), so the bag chart overfeeds them. The RER × activity × stage formula adjusts for what your specific dog actually does — that gap is usually 15-30% in our experience, which is why so many house dogs creep upward in weight.

Is the 70 × weight^0.75 formula reliable?

It's the National Research Council (NRC) 2006 standard for Resting Energy Requirement, used by veterinary nutrition courses and clinical software. It's not perfect for every individual — sighthounds and ectomorph breeds run a bit lower, mastiffs and brachycephalic breeds run higher — but it's the same starting point your vet uses before fine-tuning.

How do I read the kcal-per-cup number on the bag?

Most premium dry foods print 'Metabolizable Energy' or 'Calorie Content' as kcal per kg AND per cup. Use the per-cup number directly. If the bag only lists kcal/kg, divide by ~10 to estimate per cup (1 standard 8oz measuring cup of dry kibble is roughly 100g). Wet food calorie content is usually 80-120 kcal per 100g — much lower, so wet-food daily portions look enormous compared to dry.

What if my dog is overweight or underweight?

If your dog is more than 10% above ideal weight, calculate based on the *target* weight, not current weight. So a Labrador at 35kg whose ideal weight is 28kg should be fed for 28kg. Keep that for 4-8 weeks, weigh again, and adjust by ±10% if the trend is wrong. Underweight dogs follow the opposite — feed for current weight plus 10% and watch for steady, not rapid, gain.

Should I feed once or twice a day?

Adult dogs do well on twice daily (morning + evening). Once-a-day feeding works for adult dogs with stable weight and no GI issues but increases bloat risk in deep-chested breeds (Great Danes, German Shepherds, Standard Poodles). Puppies under 6 months need 3-4 meals daily because their stomach capacity is small and blood sugar drops between meals. Senior dogs with kidney issues sometimes do better on three smaller meals.

Why is the puppy multiplier 2.0-3.0× and not just 'more'?

Puppies under 4 months are growing tissue at the fastest rate of their entire life. NRC measured weaned puppies needing about 3× the adult RER per kilo of body weight. Between 4-12 months that drops to ~2× as growth slows. After 12 months (or later for giant breeds — 18-24 months for Great Danes), they shift to adult maintenance multipliers. Overfeeding puppies past these multipliers causes too-fast growth and joint problems, especially in large breeds.

Does breed matter beyond weight?

Less than people assume. Two 25kg dogs of different breeds need roughly the same baseline calories at the same activity level. Where breed matters: very high-drive working breeds (Border Collie, Malinois) often need the 'active' or 'working' multiplier even if they look calm at home, because they're constantly running mental laps. Brachycephalic breeds (Pugs, Frenchies) need the 'sedentary' multiplier even if they walk daily, because they can't sustain effort in heat.

What about treats and chews?

Treats should not exceed 10% of daily calories. So a 1,000 kcal/day Labrador can have ~100 kcal in treats — that's roughly 2-3 small training treats and one bully stick chew, not a whole bag of jerky. Subtract treat calories from the dinner portion if you give a lot, otherwise the dog ends up 5-15% over their daily target without anyone noticing.