Methodology & sources

Every calculator coefficient traces to a published source. In-repo packs: pipeline/AGE_MODEL_CITATIONS.md, pipeline/FOOD_MODEL_CITATIONS.md, and pipeline/BREED_DATA_CITATIONS.md, and pipeline/NUTRITION_CITATIONS.md, pipeline/COST_MODEL_CITATIONS.md, and pipeline/INSURANCE_CITATIONS.md.

• Wang (dog epigenetic): Cell Systems 2020 — 16 × ln(dog_age) + 31
• AAHA (dog size chart + nutrition factors): physiological-age poster · 2021 RER/MER box
• AAFP / AAHA (cat life stages): 2021 Feline Life Stage Guidelines
• Merck (puppy growth band): Feeding Practices in Small Animals — 2–4 g/day/kg adult
• Salt (size bands / growth standards): PLOS ONE 2017 growth standard charts
• AKC (dog breed registration ranks): Most popular dog breeds of 2025 · on-page summary
• Nutrition pack (AAFCO/FDA/WSAVA/Stockman/FDA DCM): choose food · homemade evidence · carnivores · FDA DCM
• CFA (cat breed registration ranks): Most popular breeds for 2025 (2024 regs) · on-page summary

These tools are educational. They are not veterinary advice and do not replace a veterinarian.