Convert a selected veterinary dose into total drug amount and formulation math. Weight-based arithmetic for mg/kg, mcg/kg, and mg/lb with a visible audit trail.
1. Convert entered weight to kg when the input is in lb.
2. Normalize the entered dose to mg/kg when the source dose is written as mcg/kg or mg/lb.
3. Total dose in mg = body weight x normalized dose.
4. Formulation amount = total dose divided by strength / concentration. Liquid strengths return mL. Tablet and capsule strengths return unit counts.
Display rounding is for readability only. Small totals, liquid volumes, and unit counts keep extra decimals visible so practical dosing can be checked more carefully.
Run a calculation to populate the live weight, dose, total-mg, and formulation-conversion steps here.
A 20 kg dog needs 5 mg/kg PO of a drug available as 50 mg tablets.
Total dose = 20 kg x 5 mg/kg = 100 mg
Tablet count = 100 mg / 50 mg per tablet = 2 tablets
The bedside readback is 2 tablets, after confirming route, frequency, and whether the formulation is appropriate for the patient.
Estimate the answer before revealing it: a 4 kg cat needs 0.1 mg/kg and the injectable concentration is 0.5 mg/mL.
Total dose = 4 kg x 0.1 mg/kg = 0.4 mg.
Volume = 0.4 mg / 0.5 mg/mL = 0.8 mL.
That result is arithmetic only; route, dilution needs, and syringe practicality still need review.
Last reviewed: May 2026
Sources: Plumb's Veterinary Drug Handbook; Merck Veterinary Manual