Compare your dog or cat’s weight in lb or kg with a vet target or a body condition score estimate, or estimate a healthy adult’s daily calories.
How to Use
- Select Pet type and choose weight comparison or healthy-adult energy estimation. No breed, size, sex or age database is used.
- Choose pounds (lb) or kilograms (kg), then enter Current weight.
- For a weight comparison, enter a veterinarian-set Target weight, or use the limited dog/cat BCS estimate described below.
- For adult energy, choose the applicable dog or cat category. This mode uses current weight and is only for healthy adults already at an appropriate weight.
- Select Calculate to update results. Inputs and the last successful result are stored in this browser and restored on reload; edits mark the saved result as out of date.
Notes & Tips
- A target comparison is arithmetic, not a diagnosis or a breed-based healthy range. Confirm the target with your veterinarian.
- Growing, pregnant, lactating, underweight, obese or medically affected pets need an individualized veterinary feeding plan.
- BCS assesses body fat by sight and touch. Muscle condition must be assessed separately.
- This tool is for information only and does not replace professional veterinary advice.
Pet Weight Methods & Formulas
The calculator compares current weight with a supplied target or a limited dog/cat BCS estimate. A separate mode estimates maintenance energy for healthy adult dogs and cats. These are the methods used.
1) Target Weight: T is a positive weight set with a veterinarian, or the limited BCS reference below. No breed/sex range is inferred.
2) Weight Difference: D = W − T
3) Target Comparison: compare current weight W with target T. These labels do not diagnose body condition:
- W < T → Below target
- W = T → Matches target
- W > T → Above target
4) Absolute Difference: |D| = |W − T|
5) Percent Difference from Target: 100 × (W − T) / T. Positive is above target; negative is below target.
6) Dog/Cat BCS Approximation: For scores 6–8/9 only, estimate excess weight as 10% per point above 5. Scores 4–5 are ideal-condition scores and use current weight as a reference, not a newly inferred target. Scores 1–3 or 9, and other species, require a veterinarian-set target. See AAHA’s nutritional screening guidance.
For BCS 6–8 only: T ≈ W / (1 + 0.1 × (BCS − 5)). This estimate does not define a weight-loss feeding plan.
7) Healthy-Adult Energy: Resting energy requirement (RER) = 70 × (current weight in kg)0.75 kcal/day. Maintenance energy = RER × the selected species/category factor. Individual needs vary; these starting estimates require monitoring and veterinary confirmation, not automatic diet changes. See AAHA’s healthy-weight feeding guidance.
8) Unit Conversions: 1 kg = 2.2046226218487757 lb; 1 lb = 0.45359237 kg
Variables used:
- W: current weight
- T: target or limited BCS reference weight
- D: signed difference W − T
- RER: resting energy requirement in kcal/day
- Maintenance energy: estimated daily energy at current appropriate adult weight
- BCS: Body Condition Score (1–9)
- 100 × D / T: signed percent difference from target
Units: Enter weights in pounds (lb) or kilograms (kg). Weight results include both units; the energy calculation uses kilograms. One nutritional Calorie is one kilocalorie (kcal).
What is Body Condition Score (BCS)?
For dogs and cats, BCS is a 1–9 assessment of body fat by sight and touch. Muscle condition is a separate assessment; an overweight pet can also lose muscle. Have your veterinary team confirm both assessments.
- 1–3: Underweight — ribs, spine, and hip bones very easy to feel/see; minimal fat coverage.
- 4–5: Ideal — ribs palpable without excess fat; waist visible from above; abdominal tuck from the side.
- 6–9: Overweight to Obese — ribs difficult to feel; little waist/abdominal tuck; increasing fat deposits.
