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, reminders, and more â free during early access.
ðū Join the Early Access Waitlist