Educational reference only. RER and the MER factors above are commonly published convention ranges — actual caloric needs vary significantly by individual metabolism, activity, and body condition. Use body condition score and weight trend over time to adjust, not this table alone, and confirm any diet plan with the attending veterinarian.
Commonly published convention for an intact, healthy adult dog at maintenance.
Enter a weight above to calculate RER and MER.
How This Calculator Works
RER is calculated with the commonly published allometric formula:
RER (kcal/day) = 70 × body weight (kg)^0.75
MER then scales RER by a life-stage/activity factor from the commonly published convention table — for example 1.6× for a neutered adult dog, or 3.0× for a puppy under 4 months:
MER (kcal/day) = RER × life-stage factor
Worked Example
A 20 kg neutered adult dog at maintenance:
RER = 70 × 20^0.75 ≈ 662 kcal/day
MER = 662 × 1.6 ≈ 1059 kcal/day
Frequently Asked Questions
What is RER and how is it calculated?
RER (Resting Energy Requirement) is the estimated number of calories a patient needs at complete rest. It is commonly calculated as 70 × body weight in kilograms, raised to the power of 0.75 — a widely published convention that scales more accurately across very small and very large patients than a simple linear formula.
What is MER and how does it differ from RER?
MER (Maintenance Energy Requirement) adjusts RER for a patient's actual life stage and activity level, since resting energy alone underestimates real-world needs. MER = RER × a life-stage/activity factor — for example, a neutered adult dog is commonly given a factor around 1.6, while a growing puppy under 4 months is commonly given a factor around 3.0.
Why do the MER factors show a range instead of one number?
Several life stages — like weight gain, active/working dogs, and lactation — have commonly published convention ranges rather than a single factor, because caloric needs at those stages vary more with individual circumstances (workload, litter size, stage of lactation) than a fixed multiplier can capture.
Are these factors accurate for every individual patient?
No — they are commonly published convention ranges intended as a starting point, not a guarantee. Actual caloric needs vary significantly by individual metabolism and activity. Body condition score and weight trend over time are better indicators of whether the current intake is appropriate, and the plan should be adjusted accordingly.
Should a weight-loss plan use the patient's current weight or target weight?
Conventions vary by protocol; the calculation here uses the entered weight directly with the weight-loss factor (commonly 1.0 × RER). Many weight-loss protocols reassess and recalculate as the patient loses weight rather than using a single static target-weight calculation throughout.
Does this tool account for prescription/therapeutic diets?
No — it estimates a general caloric target only. Feeding amounts for a specific diet should be calculated from that product's actual kcal/cup or kcal/can density, and any therapeutic diet plan should be set in consultation with the attending veterinarian.
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Related Resources
Veterinary Physical Exam Form Template
Track weight and body condition alongside a caloric target.
Veterinary Discharge Instructions Template
Send home feeding guidance alongside other post-visit instructions.
Veterinary Treatment Sheet Template
Log caloric intake for hospitalized patients on a shared grid.
Body Condition Score (BCS) Chart
The 1–9 scale behind the condition input that drives energy targets.