The exact veterinary formula behind MyPetDex's Calorie Calculator â how it works, worked examples, and why you can trust the numbers.
Try the Calculator âMyPetDex doesn't guess at portions. Every recommendation starts from Resting Energy Requirement (RER) â the calories your pet's body burns at complete rest â then adjusts for how active they are and what life stage they're in.
From there, we calculate Maintenance Energy Requirement (MER) â the number that actually tells you how much to feed:
Three real scenarios, calculated step by step using the exact same lookup table as the calculator on our homepage.
This is the single biggest factor pet owners get wrong â and it changes depending on whether your pet is spayed/neutered or intact.
Based on current weight, not activity: under 2 kg Ã3.0, 2â10 kg Ã2.5, over 10 kg Ã2.0. Growing bodies need significantly more energy regardless of how active they seem.
Brief bathroom-break walks only, rests most of the day.
30â60 minutes of walking or play daily â fits most household pets.
1â2+ hours of daily exercise â hiking, running, swimming, working/sporting dogs.
Metabolism slows with age, but protein needs stay high. Senior-formulated food with joint support is worth considering.
Energy needs rise sharply, especially in the final third of pregnancy.
The highest energy demand of any life stage â nursing mothers may need to eat multiple times their normal maintenance amount.
The life-stage factor gets a final nudge based on where your pet sits on the 9-point Body Condition Score (BCS) scale â pulling the target up for underweight pets and down for overweight ones.
Portions increased to help rebuild healthy weight.
A small boost above baseline maintenance.
No adjustment â this is the target most pets should be maintained at.
Portions reduced to bring weight back down gradually.
A significant reduction â pair with your vet's guidance for a safe weight-loss plan.
Every pet's metabolism is a little different. Recheck body condition every 2â4 weeks and adjust from there.
The official U.S. nutrient profile standard for pet food, covering every life stage.
400,000+ ingredient entries from the U.S. government's public nutrition database.
The global RER formula used by veterinarians worldwide â the same one powering this calculator.
It uses the same RER/MER formula taught in veterinary nutrition programs and referenced by WSAVA. It's a strong starting point, but every pet's metabolism varies â treat the result as a baseline to adjust from, not a fixed rule.
Some breeds run leaner or heavier metabolisms than average (sighthounds vs. brachycephalic breeds, for example). Start with the calculated number, then adjust based on body condition over a few weeks.
Most adult dogs and cats do well on 2 meals a day. Puppies and kittens typically need 3â4 smaller meals to support growth and blood sugar stability.
Yes â treats should make up no more than about 10% of daily calories. Large or frequent treats can throw off the whole calculation.
Calorie targets, vaccine records, and reminders will live in the iPhone app when it launches.
Coming soon to the App Store