About Calculators for Dogs
Calculators for Dogs is an independently built and maintained collection of free tools for dog owners. Every calculator implements a published, citable formula, and every page states which one.
What this site is not
These calculators are not reviewed by a veterinarian. This site is not run by a veterinary practice and does not employ veterinary staff. The tools implement formulas published by the organisations listed below, but no licensed professional signs off on the individual pages.
That matters most on the medication and toxicity calculators. Use them to understand a situation and to prepare for a conversation with your vet. Do not use them in place of one. If your dog has ingested something toxic or you are considering a dose, call your veterinarian or the ASPCA Animal Poison Control Center on (888) 426-4435 straight away.
How the calculators are built
Each calculator starts from a formula that already exists in the veterinary or nutrition literature. We do not invent formulas. Where a published equation exists, we implement it as written and cite it on the page. Where a range or threshold is involved, we show the range rather than collapsing it into a single false-precise number.
Where two accepted methods disagree, we show both and explain the disagreement rather than silently picking one. The dog age calculator is the clearest example: the size-based veterinary chart and the 2020 DNA-methylation clock differ by up to 20 human years for young dogs, and the page reports the range and the point where they converge.
Formulas and reference data are reviewed when the underlying source is updated, and each calculator page carries its own sources and stated limitations.
Where the numbers come from
| Source | What it is used for |
|---|---|
| AAFCO Nutrient Profiles | Minimum and maximum nutrient levels used by the nutrition and diet calculators. |
| NRC Nutrient Requirements of Dogs and Cats (2006) | Resting energy requirement and maintenance energy formulas, including RER = 70 x (body weight in kg)^0.75. |
| WSAVA Global Nutrition Guidelines | The 9-point body condition score used across the weight and feeding calculators. |
| WALTHAM Petcare Science Institute growth charts | Puppy growth curve percentages behind the weight and size predictors. |
| American Kennel Club breed standards | Published adult weight and size ranges for individual breeds. |
| ASPCA Animal Poison Control Center thresholds | Toxic dose thresholds for the chocolate, xylitol, grape, onion, garlic and related toxicity calculators. |
Corrections
If you find a formula, threshold or figure on this site that is wrong, we want to know and we will fix it. Accuracy complaints are treated as the highest priority of any feedback we receive. Reach us through the contact page.
Always consult your veterinarian
Calculators work from population averages. Your dog is an individual, and factors these tools cannot see, including body condition, organ function, concurrent medication and breed-specific sensitivity, change the right answer. Treat every result here as a starting point for a conversation with the person who has actually examined your dog.