Pets & Animals Calculators

About these pets & animals calculators

Animal nutrition has a genuine equation at its core. Resting energy requirement scales with body weight to the power of 0.75, not linearly, which is why a 40 kg dog does not need twice the food of a 20 kg one. Multiply that resting figure by a factor for age, activity and whether the animal is neutered, and you have a daily calorie target that is accurate enough to feed from. The dog and cat calculators both run this, and both also offer the simpler percentage-of-body-weight method that raw feeders use.

Housing has equations too, and they are less forgiving than people expect. Four square feet of coop per hen is a floor, not a target, and crowding below it produces feather-picking and disease faster than any other single mistake. Aquarium turnover of four to six times the tank volume per hour is what keeps a filter ahead of the bioload. Heater wattage depends on the gap between room temperature and target temperature, not on tank size alone.

Two cautions run through this cluster. The first is that stocking rules of thumb — the classic one inch of fish per gallon — are starting points that break badly for heavy-waste species. A single goldfish outproduces several inches of tetra. The calculator says so rather than quietly returning a number that will kill fish. The second is that every feeding figure here is a starting point to be adjusted by watching the animal: body condition, energy, coat and stool tell you more than any formula.

Nothing here replaces a vet. Feeding changes, weight-loss plans and raw diets in particular need professional input — cats can develop hepatic lipidosis if they lose weight too fast, and raw diets need correct ratios and supplementation to be complete. Use these numbers to have a better-informed conversation, not to avoid one.