Levothyroxine Dosage Calculator for Dogs
Calculate the weight-based levothyroxine dose for dogs with frequency and safety guidance.
What Is the Levothyroxine Dosage Calculator for Dogs?
Calculate the weight-based levothyroxine dose for dogs with frequency and safety guidance.
This calculator gives the standard weight-based dose range for hypothyroidism (underactive thyroid) in dogs — the most common endocrine disease in dogs. Always verify with your vet before administering.
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
Fill in the required fields above — typically your dog's weight, age, or breed size. Every field has a clear label and hint.
Press the calculate button to get your instant result. No page reload, no account needed, no waiting.
Your result appears immediately below the calculator. It includes the primary answer plus additional context where relevant.
Share, print, or save your result. Always discuss health-related results with your veterinarian before making decisions.
How It Works
Dog medication dosing is weight-based — expressed as mg per kg of bodyweight. This calculator multiplies your dog's weight by the established therapeutic dose range to give the actual mg to administer. Always start at the lower end and adjust under veterinary supervision. Prescription medications require a valid veterinary prescription in all jurisdictions.
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.
100% Private
All calculations happen in your browser. Nothing you enter is ever stored on our servers or shared with anyone.
Always Free
Every calculator on Doggy Calculators is and will always be completely free to use — no premium tier, no catch.
Frequently Asked Questions
Sources & References
This calculator's formulas are based on the following peer-reviewed and authoritative veterinary sources:
- Plumb's Veterinary Drug Handbook (9th Edition) — Primary reference for all dosage ranges and frequency guidance
- Merck Veterinary Manual — Drug pharmacology, indications, and contraindications
- WSAVA Global Nutrition Guidelines — Weight-based dosing principles and patient monitoring
- VCA Animal Hospitals Drug Library — Client-facing drug information and safety guidance
⚠️ These calculators are reference tools only. Always consult a licensed veterinarian before administering medication or making medical decisions.