Cat Ideal Weight Calculator (BCS)
Estimate your cat’s ideal weight using a simple Body Condition Score (BCS) approach. Get an ideal range and how much weight to lose or gain.
Quick answer
BCS quick guide (1–9)
BCS 4–5 is often considered “ideal.” Higher scores suggest extra body fat; lower scores suggest underweight. This calculator uses a simple rule-of-thumb to estimate an ideal weight range.
This is not a diagnosis. For medical advice or a weight-loss plan, talk to your vet.
Inputs
Use a recent scale reading.
4–5 is often considered ideal.
Optional: frame size
This slightly widens/narrows the ideal range.
Most cats aim for 4–5. Use vet guidance if unsure.
BCS quick guide (simple)
Use this as a quick self-check.
If you’re unsure, a veterinarian can score BCS quickly and safely.
Next step: build a weight loss plan
Once you know the goal range, you can estimate a safe timeline (for example, around 0.5–1% of body weight per week). This site can link to a separate “Cat Weight Loss Calculator” page.
How this calculator works (formulas)
This calculator uses a simple rule-of-thumb: each step above or below the target BCS represents about ~10% body weight difference. It’s a practical estimate, not a clinical measurement.
Step 1: Choose a target BCS
Most cats aim for BCS 5 (sometimes 4 for a leaner target).
Step 2: Estimate ideal weight
IdealWeight ≈ CurrentWeight ÷ (1 + 0.10 × (BCS − TargetBCS)) (if BCS is above target)
IdealWeight ≈ CurrentWeight ÷ (1 − 0.10 × (TargetBCS − BCS)) (if BCS is below target)
Step 3: Show a range
We also display an ideal range between BCS 4–5 (or 5–4 if you chose a leaner target), then apply a small “frame size” adjustment (small/large).
If you’re uncertain about BCS or your cat has health issues, consult a veterinarian.
FAQ
What is a cat BCS (Body Condition Score)?
BCS is a 1–9 scoring system vets use to estimate body fat based on ribs, waist, and overall shape. Many cats are considered ideal around BCS 4–5.
Is this ideal weight exact?
No. It’s a practical estimate. Breed, frame size, muscle mass, age, and health conditions affect ideal weight. Use this as a starting point and confirm with your vet when possible.
How fast should a cat lose weight?
Many weight-loss plans target a slow pace (for example ~0.5–1% of body weight per week). Rapid weight loss can be dangerous for cats. Always use vet guidance for overweight cats.