Convert a continuous-rate infusion plan into drug-per-hour and infusion-rate math. Optional dilution inputs show the final bag concentration needed over the planned duration, with a visible arithmetic trail for mg/kg/hr and mcg/kg/min entries.
1. Convert entered weight to kg when the input is in lb.
2. Normalize the entered rate to mg/kg/hr when the source rate is written in mcg/kg/min.
3. Drug required per hour = body weight x normalized rate.
4. Infusion rate (mL/hr) = mg/hr divided by stock concentration.
5. Optional dilution math adds total drug over the selected duration, then divides by total fluid volume.
Display rounding is for readability only. Small infusion rates keep extra decimals visible so pump settings can be checked more carefully.
Calculation steps will appear here for verification.
A 20 kg dog needs a CRI at 5 mcg/kg/min from a stock solution labeled 10 mg/mL.
5 mcg/kg/min = 0.3 mg/kg/hr
20 kg x 0.3 mg/kg/hr = 6 mg/hr
6 mg/hr / 10 mg/mL = 0.6 mL/hr
The practical readback is 0.6 mL/hr from the entered stock concentration, delivering 6 mg/hr.
Estimate the answer before revealing it: a 4.5 kg cat has a target CRI of 0.15 mg/kg/hr and the stock concentration is 5 mg/mL.
Drug required per hour = 4.5 kg x 0.15 mg/kg/hr = 0.675 mg/hr.
Infusion rate = 0.675 mg/hr / 5 mg/mL = 0.135 mL/hr.
This is the kind of very small rate that should trigger a pump-precision double-check.
Last reviewed: May 2026
Sources: Plumb's Veterinary Drug Handbook; BSAVA Formulary