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Dog Weight Loss Calculator

Build a safe, vet-approved weight loss plan for your dog with realistic targets and calorie-controlled portions.

🏋️ Dog Weight Loss Calculator
Enter your dog's details below to get an instant result.
Daily Food Target
-g/day
-
Daily kcal
-
Weeks to goal
Warning: Weight loss in dogs should always be gradual. Never reduce food by more than 20-25% at once. Reweigh every 2 weeks and adjust portions if progress stalls. Consult your vet before starting a weight loss programme.

What Is the Dog Weight Loss Calculator?

Build a safe, vet-approved weight loss plan for your dog with realistic targets and calorie-controlled portions.

Over 55% of dogs are overweight. Excess weight shortens lifespan, worsens joint disease, and increases disease risk. This calculator builds a safe, science-based weight loss programme with weekly targets and adjusted daily food portions.

Every result is based on published veterinary research and breed-size-specific growth data — not generic averages. This tool is completely free, works instantly in your browser, and requires no account or sign-up.

How to Use This Calculator

1
Enter Your Dog's Details

Fill in the required fields above — typically your dog's weight, age, or breed size. Every field has a clear label and hint.

2
Click Calculate

Press the calculate button to get your instant result. No page reload, no account needed, no waiting.

3
Review Your Result

Your result appears immediately below the calculator. It includes the primary answer plus additional context where relevant.

4
Use the Information

Share, print, or save your result. Always discuss health-related results with your veterinarian before making decisions.

How It Works

For weight loss, we use the target weight (not current weight) in the RER formula — 70 x (target weight)^0.75. This calculates the calories needed to maintain the target weight rather than the current weight, creating a calorie deficit. We then apply a further 0.8 multiplier (80% of target maintenance) to accelerate loss safely.

Weekly loss rate is expressed as a percentage of current bodyweight. At 1.5% per week, a 30kg dog loses approximately 450g weekly — safe, gradual, and sustainable. Faster than 2% risks muscle loss and nutritional deficiency. The estimated timeline assumes consistent adherence to the new portion.

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Veterinary Research

Every formula is derived from peer-reviewed veterinary studies and clinical guidelines, not guesswork or generic rules.

Instant Results

No page reload, no waiting, no account needed. Enter your details and your result appears immediately.

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100% Private

All calculations happen in your browser. Nothing you enter is ever stored on our servers or shared with anyone.

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Always Free

Every calculator on Doggy Calculators is and will always be completely free to use — no premium tier, no catch.

Frequently Asked Questions

How long will it take my dog to reach their target weight?+
The calculator estimates weeks based on your chosen loss rate. At the recommended 1.5% per week, a dog needing to lose 5kg takes approximately 16-20 weeks. Consistency matters more than speed.
My dog is always hungry on the diet — what can I do?+
Feed more frequent smaller meals (3 instead of 2). Add low-calorie volume foods like boiled green beans or carrots. Use a slow feeder bowl to extend eating time. Ensure the calorie deficit is not too aggressive.
Should I change to a diet food?+
Many prescription weight loss foods have lower calorie density, allowing larger portion sizes that keep dogs feeling fuller. Ask your vet whether a prescription diet food is appropriate for your dog.
How do I know if the weight loss plan is working?+
Reweigh every 2 weeks at the same time of day on the same scales. If losing more than 2% per week, increase portions by 5%. If not losing after 4 weeks, reduce by 5-10% and recheck.
Can exercise help my dog lose weight?+
Yes — exercise combined with calorie reduction is more effective than either alone. Exercise also preserves muscle mass during weight loss. Start gently and increase duration gradually for overweight dogs with joint issues.

Sources & References

This calculator's formulas are based on the following peer-reviewed and authoritative veterinary sources:

⚠️ These calculators are reference tools only. Always consult a licensed veterinarian before administering medication or making medical decisions.