Canine Drug Dose Calculator
Accurate drug dosing in dogs is essential for safe and effective treatment. Most veterinary drugs are prescribed by your vet as a dose rate in milligrams per kilogram (mg/kg) of body weight. To find the total dose your dog requires, you simply multiply the dose rate by the dog's weight in kilograms. This calculator handles the arithmetic, including a pounds-to-kilograms conversion if you weigh your dog in pounds. It also optionally divides the total dose by tablet strength to show how many tablets are needed. Always confirm the prescribed dose rate, frequency, and any rounding instructions with your licensed veterinarian before administering any medication.
Canine drug dosing formula
Total dose (mg) = Dose rate (mg/kg) x Body weight (kg)
If weight in lb: Weight (kg) = Weight (lb) / 2.2046
Tablets = Total dose (mg) / Tablet strength (mg)
The dose rate is always determined by your veterinarian based on the specific drug, condition being treated, and the individual animal's health status. This calculator performs only the arithmetic step of multiplying rate by weight.
Understanding weight-based dosing
- Larger dogs receive more total milligrams but at the same mg/kg rate as smaller dogs.
- Puppies and senior dogs may require adjusted dose rates due to different drug metabolism; consult your vet.
- Always weigh your dog at the time of dosing, as weight can change with illness.
- Some drugs have a maximum dose ceiling regardless of weight; your vet will specify this.
- Frequency of dosing (once daily, twice daily, etc.) is separate from the per-dose calculation shown here.
Canine drug dose calculator: frequently asked questions
How is a canine drug dose calculated?
The standard method is: Total dose (mg) = dose rate (mg/kg) multiplied by the dog's body weight (kg). Your veterinarian prescribes the dose rate based on the drug and condition; you multiply it by weight to get the total milligrams required.
Can I convert pounds to kilograms in this calculator?
Yes. Enter the weight in pounds and select the lb option. The calculator converts using 1 lb = 0.4536 kg before computing the dose, so you get an accurate milligram total from a pound-based weight.
What is a typical dose rate for common canine medications?
Dose rates vary enormously by drug. For example, amoxicillin is commonly 10-20 mg/kg, carprofen is around 2-4 mg/kg per day, and metronidazole is 10-15 mg/kg. Always follow your veterinarian's specific prescription for your dog's condition.
How do I calculate how many tablets to give?
Divide the total dose in mg by the tablet strength in mg. For example, if the total dose is 250 mg and each tablet is 100 mg, you need 2.5 tablets. Your vet may round to a practical tablet count.
Is this calculator a substitute for veterinary advice?
No. This tool performs the arithmetic of mg/kg dosing as a reference aid. The dose rate, frequency, duration, and suitability for your dog must always be determined by a licensed veterinarian who has examined the animal.
Official sources
- American Animal Hospital Association (AAHA): AAHA Homepage.
- USDA Animal and Plant Health Inspection Service: APHIS Homepage.
- FDA Center for Veterinary Medicine: Animal and Veterinary.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.