Pet Medication Dosage Calculator
For general reference only. Always consult a veterinarian before administering any medication — not professional veterinary advice.
Converting a Dose Rate Into an Actual Amount
Veterinary medications are prescribed as a rate — milligrams per kilogram of body weight — not a fixed amount, because a dose that's appropriate for a 5-pound cat would be dangerously inadequate or excessive for a 50-pound dog. This calculator converts a prescribed dose rate and an animal's weight into the total milligram dose, and, if you know the drug's concentration, the exact volume to measure out.
The Formula
Weight entered in pounds is converted to kilograms first, using the standard conversion factor of 1 lb = 0.453592 kg.
Worked Example
A 12 kg dog prescribed a 5 mg/kg dose, using a medication concentrated at 50 mg/mL:
| Step | Calculation | Result |
|---|---|---|
| Total dose | 12 kg × 5 mg/kg | 60 mg |
| Volume to administer | 60 mg ÷ 50 mg/mL | 1.2 mL |
A 22 lb animal converts to approximately 9.979 kg using the standard pound-to-kilogram factor, before the dose calculation is applied.
Where This Calculation Matters
- Weight-based prescriptions — translating a veterinarian's mg/kg instruction into the actual milligram amount for a specific animal.
- Liquid medication measuring — converting a milligram dose into a syringe or dropper volume based on the product's labeled concentration.
- Cross-checking a prescription label — verifying that a dispensed volume matches the prescribed dose rate for the animal's recorded weight.
How to Use This Calculator
- Select the Species (dog, cat, or other).
- Enter the animal's Weight and choose the unit (kg or lb).
- Enter the prescribed Dose Rate in mg/kg.
- Optionally enter the medication's Drug Concentration in mg/mL to also get a volume to administer.
- Select Calculate to see the total dose (and volume, if concentration was entered).
Related Calculations
For dosing with a narrower safety margin, see the Pet Anesthesia Dosage Calculator, or estimate ongoing costs with the Vet Bill Estimate Calculator.