Sources & references

Every constant and formula used on this site comes from one of the references below. Each tool page also lists the specific sources behind that tool, directly under its formula.

41 of 43 references link to the document itself. The rest are real publications with no stable free URL we could confirm, so they are listed as plain text rather than pointed at a link that might be wrong.

Nutrition and energy requirements

• National Research Council. Nutrient Requirements of Dogs and Cats. Washington, DC: National Academies Press; 2006.
• WSAVA Global Nutrition Committee. Global Nutrition Guidelines and toolkit.
• American Animal Hospital Association. 2021 AAHA Nutrition and Weight Management Guidelines for Dogs and Cats.
• Association of American Feed Control Officials. Understanding Pet Food: labeling, calorie content statements and the modified Atwater factors.
• US Department of Agriculture, Agricultural Research Service. FoodData Central.
• German AJ, Holden SL, Mason SL, Bryner C, Bouldoires C, Morris PJ, Deboise M, Biourge V. Imprecision when using measuring cups to weigh out extruded dry kibbled food. J Anim Physiol Anim Nutr (Berl). 2011;95(3):368–373. Accuracy ranged from an 18% under-estimate to an 80% over-estimate of portion size.
• Coe JB, Rankovic A, Edwards TR, Parr JM. Dog owner's accuracy measuring different volumes of dry dog food using three different measuring devices. Vet Rec. 2019;185(19):599.
• FEDIAF (European Pet Food Industry Federation). Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs.
• Stockman J, Fascetti AJ, Kass PH, Larsen JA. Evaluation of recipes of home-prepared maintenance diets for dogs. J Am Vet Med Assoc. 2013;242(11):1500–1505. Of 200 recipes assessed, none provided all essential nutrients at recommended concentrations.

Body condition and weight

• Laflamme DP. Development and validation of a body condition score system for dogs. Canine Practice. 1997;22(4):10–15. The original validation of the 9-point scale. No free full text; the reference is listed on the Purina Institute page below.
• Purina Institute. The Purina Body Condition System (9-point scale for dogs and cats).
• WSAVA Global Nutrition Committee. Body Condition Score chart for dogs (PDF).
• Kealy RD, Lawler DF, Ballam JM, Mantz SL, Biery DN, Greeley EH, Lust G, Segre M, Smith GK, Stowe HD. Effects of diet restriction on life span and age-related changes in dogs. J Am Vet Med Assoc. 2002;220(9):1315–1320. The Labrador lifespan study: lean-fed dogs lived a median 1.8 years longer.

Aging and life stages

• American Animal Hospital Association. 2019 AAHA Canine Life Stage Guidelines.
• American Kennel Club. How to calculate dog years to human years.
• Wang T, Ma J, Hogan AN, Fong S, Licon K, et al. Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome. Cell Syst. 2020;11(2):176–185.e6. The epigenetic clock. Derived from 104 Labrador retrievers, so it is breed-specific in origin.

Toxicology

• Merck Veterinary Manual. Chocolate Toxicosis in Animals.
• Merck Veterinary Manual. Garlic and Onion (Allium spp) Toxicosis in Animals.
• Merck Veterinary Manual. Grape, Raisin, and Tamarind (Vitis spp, Tamarindus spp) Toxicosis in Dogs.
• Merck Veterinary Manual. Xylitol Toxicosis in Dogs.
• ASPCA Animal Poison Control Center. People foods to avoid feeding your pets.
• Pet Poison Helpline. 24/7 Animal Poison Control Center.
• Merck Veterinary Manual. Macadamia Nut Toxicosis in Dogs.
• Merck Veterinary Manual. Avocado (Persea spp) Toxicosis in Animals.
• Merck Veterinary Manual. Bread Dough Toxicosis in Animals.
• Merck Veterinary Manual. Salt Toxicosis in Animals.
• Merck Veterinary Manual. Toxicoses From Alcohols in Animals.
• Merck Veterinary Manual. Food Hazards (toxicology section index).
• US Food and Drug Administration. Paws Off Xylitol; It's Dangerous for Dogs.
• Wegenast CS, Meadows ID, Anderson RE, Southard T, González Barrientos CR, Wismer TA. Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds and the connection to tartaric acid as the proposed toxic principle in grapes and raisins. J Vet Emerg Crit Care. 2022;32(6):812–816.

Preventive care and schedules

• American Animal Hospital Association. 2022 AAHA Canine Vaccination Guidelines (updated 2024). J Am Anim Hosp Assoc. 2022;58:1–19.
• WSAVA Vaccination Guidelines Group. Guidelines for the Vaccination of Dogs and Cats.
• Companion Animal Parasite Council. General Guidelines for Dogs and Cats (year-round parasite control).
• ESCCAP Guideline 1. Worm Control in Dogs and Cats.
• ESCCAP Guideline 3. Control of Ectoparasites in Dogs and Cats.
• Merck Veterinary Manual. Gastrointestinal Parasites of Dogs.

Reproduction

• Merck Veterinary Manual. Breeding Management of Bitches (estrous cycle and gestation).
• Johnston SD, Root Kustritz MV, Olson PNS. Canine and Feline Theriogenology. Philadelphia: WB Saunders; 2001. Standard reference text for canine gestation length and whelping. No free full text.

Behavior, welfare and safety

• American Veterinary Society of Animal Behavior. Position Statement on Puppy Socialization (PDF).
• RSPCA. Keeping your dog company: guidance on leaving dogs alone.
• American Veterinary Medical Association. Warm weather pet safety.
• IATA. Live Animals Regulations, including Container Requirement 1 for dogs and cats.
• Hall EJ, Carter AJ, O’Neill DG. Incidence and risk factors for heat-related illness (heatstroke) in UK dogs under primary veterinary care in 2016. Sci Rep. 2020;10:9128.

A note on ranges

Where two reputable sources disagree, we show the range rather than picking a favorite. Where a source gives a range itself, such as the energy multiplier for working dogs, that range is carried through to the result instead of being averaged into a single misleading figure.

Where a source does not exist

Some of what the sizing tools rely on is trade convention rather than published science: crate dimensions, collar sizing, the month-plus-one house training rule. Those pages say so in place of the citation, because dressing a convention up as a reference is worse than admitting it is a convention.

Spotted an error or a better source? Tell us. Corrections to the underlying math are the most useful thing you can send.