Dog calculators that show their working
Free tools for the questions dog owners actually search at 11pm. Every calculation runs in your browser, nothing is sent anywhere, and every formula is written out on the page with its source.
3 of 39 planned tools are live.
Available now
- Dog Calorie Calculator
Calculate how many calories your dog needs per day from body weight, life stage and activity level, using the standard RER and MER veterinary formulas.
- Dog Age Calculator
Convert your dog’s age into human years using size-adjusted veterinary life-stage data instead of the inaccurate multiply-by-seven rule.
- Dog Chocolate Toxicity Calculator
Find out how dangerous the chocolate your dog ate is, by calculating the theobromine dose in mg per kg of body weight and the symptoms expected at that dose.
Browse by category
- Dog Feeding Calculators
Work out how much to feed your dog: daily calories, portion sizes by brand, treat budgets, raw and homemade rations, and water intake.
- Dog Health Calculators
Dog age in human years, ideal weight, body condition score, safe weight-loss planning, and puppy growth predictions.
- Dog Care Schedule Calculators
Build vaccination, deworming and parasite-prevention timelines, plus pregnancy due dates and heat cycle predictions.
- Dog Safety & Toxicity Calculators
Check whether what your dog ate is dangerous: chocolate, grapes, xylitol, onion and garlic doses by body weight, plus heat safety.
- Dog Sizing & Cost Calculators
Size a crate, collar, harness, bed or dog door correctly, check airline crate rules, and estimate exercise needs and ownership cost.
Why another dog calculator site
Most dog calculators give you a number and nothing else. You cannot tell whether the answer came from a veterinary formula or from a guess, which matters a great deal when the question is how much chocolate is dangerous.
Every tool here shows the formula it used, the constants it used, and where those constants come from. The calculation code is separated from the interface and covered by unit tests, so the arithmetic is checked rather than assumed. Where the science is uncertain, the page says so instead of rounding it away.
None of this replaces a vet. It is meant to help you arrive at the appointment already knowing what to ask, and to tell you when the appointment needs to be right now.