Why this site exists
Most pet calculators online run on folklore: multiply dog years by seven, feed a cup or two, hope for the best. Meanwhile, the actual formulas — the ones taught in veterinary nutrition and printed in the Merck Veterinary Manual — sit in places pet owners never look. FurCalcs closes that gap. Every calculator here implements a published veterinary formula or guideline, shows its work, and links to the primary source so you can verify it yourself.
Where the numbers come from
- Energy and feeding: the RER/MER equations (70 × kg0.75) with life-stage factors from the Ohio State Veterinary Medical Center and the Merck Veterinary Manual
- Toxicity: methylxanthine content and dose thresholds from the Merck Veterinary Manual, with the Pet Poison Helpline for emergencies
- Aging and life stages: AKC/AVMA size-adjusted aging, AAHA canine life stages, and the 2021 AAHA/AAFP feline life stage guidelines
- Weight management: the AAHA 2014 body-condition-score method (each point ≈ 10% from ideal)
- Reproduction: gestation windows and dystocia criteria from the Merck Veterinary Manual
Where no scientific standard exists — small-pet age conversions, for instance — we say so plainly on the page and explain the estimation method we chose instead of dressing a convention up as science.
What we will never do
FurCalcs is information, not diagnosis. We don't do medication dosing calculators, we don't answer "is my pet sick" questions, and every health-adjacent page carries the same advice: when in doubt, call your veterinarian. A calculator's job is to make you a better-informed pet owner on the way to the clinic, not to keep you from going.
Contact
Found an error in a formula, a source that's gone stale, or a calculator you wish existed?Tell us — corrections ship fast here.