What this site can and cannot calculate
The calculators provide educational references and explicit arithmetic. They do not measure a dog's DNA, diagnose health, or predict an individual date of death. A population statistic cannot be made into an individual forecast simply by adding more inputs.
Breed lifespan references
McMillan et al. (2024), Longevity of companion dog breeds: those at risk from early death, combined multiple UK sources covering 584,734 dogs. It is not solely an RVC VetCompass primary-care dataset. Supplementary Table S3 reports breed-specific estimated median survival, confidence intervals, deaths and censored observations.
On 20 October 2026 we checked the original Table S3 against the site's legacy records. There are 134 matched breed records with a matching name or unambiguous alias and median. Five legacy study-labelled records remain under review: Cocker Spaniel, Belgian Malinois, Russell Terrier, Standard Poodle and Swedish Vallhund. Their disputed study numbers are withheld from the lifespan page and calculator reference. We have not inferred replacements.
A median is not an arithmetic average. Its 95% confidence interval expresses uncertainty in that population estimate. The interval is not a minimum/maximum age or a prediction interval for one dog. Other breed references are labelled as estimates; a link to the paper alone does not establish a direct study median for a mixed or designer breed.
Age comparisons
Wang et al. (2020) studied 104 Labrador Retrievers. The work appeared as a preprint in 2019 and in Cell Systems in 2020. The mapping 16 × ln(dog age) + 31 is used here as an educational comparison. It does not measure the individual dog's methylation, and we have not validated it for every breed. The separate size-based reference does not modify that equation.
Age divided by a breed reference, multiplied by 100, is an age/reference percentage. It is not a survival percentile. The life-expectancy tool does not subtract age from a median or add fixed body-condition penalties. It displays the source reference and its limits.
Food units and calorie assumptions
The food tool starts with RER = 70 × kg^0.75 and applies the site's disclosed activity and life-stage assumptions. Their combined output is a starting estimate, not a validated individual prescription. The MSD Veterinary Manual explains energy requirements and individual adjustment; it does not validate every factor in this implementation.
An optional user-entered daily calorie target replaces that estimate. The site cannot verify who provided the target. Cups equal daily calories divided by the label's kcal per cup. Grams require grams per cup, or derive from kcal per cup ÷ kcal per kg × 1000. Without mass information, grams are unavailable. Do not substitute kcal per can for kcal per cup. AAFCO's calorie guidance explains label units; AAFCO is not cited as the source of this site's activity multipliers.
Remaining limitations
Legacy articles and other calculators require separate source review. A source link or an editorial date does not mean every individual health claim has received veterinary review. Individual care, prescribed diets and clinical prognosis belong with a veterinarian who knows the dog.
