mcg/kg/min Calculator: Weight-Based Drips
Vasoactive drips like dopamine and dobutamine are ordered in mcg/kg/min; weight-based heparin in units/kg/hr. Enter the weight, the bag, and the order or the pump rate.
Shows the work. Answer, formula, and numbered steps, rounded the way nursing exams expect. For study and exam practice, not for patient care.
Formula
mL/hr = mcg/kg/min × kg × 60 ÷ mcg per mL.
Fill in the fields and press Calculate to see the answer and every step.
For study and exam practice, not for patient care.
Rounding: Pump rates under 100 mL/hr round to the tenth; 100 mL/hr or more, to a whole number. A dose per kg rounds to the hundredth.
Terms: mcg, Titration, Concentration
Worked examples
Dopamine 2.5 mcg/kg/min is ordered for a client who weighs 123 kg. The bag is dopamine 400 mg in 250 mL.
- Solve for
- Pump rate (mL/hr)
- Ordered dose
- 2.5 mcg/kg/min
- Weight
- 123 kg
- Drug in the bag
- 400 mg
- Bag volume
- 250 mL
Formula mL/hr = mcg/kg/min × kg × 60 ÷ mcg per mL.
- Concentration = 400,000 mcg ÷ 250 mL = 1,600 mcg/mL.
- Dose per hour = 2.5 mcg/kg/min × 123 kg × 60 min/hr = 18,450 mcg/hr.
- mL/hr = 18,450 mcg/hr ÷ 1,600 mcg/mL = 11.53 mL/hr.
- Below 100 mL/hr the pump is set to the nearest tenth: 11.5 mL/hr.
Answer 11.5 mL/hr
Start a heparin infusion at 18 units/kg/hr for a client who weighs 80 kg. The bag is heparin 25,000 units in 250 mL.
- Solve for
- Pump rate (mL/hr)
- Ordered dose
- 18 units/kg/hr
- Weight
- 80 kg
- Drug in the bag
- 25,000 units
- Bag volume
- 250 mL
Formula mL/hr = mcg/kg/min × kg × 60 ÷ mcg per mL.
- Concentration = 25,000 units ÷ 250 mL = 100 units/mL.
- Dose per hour = 18 units/kg/hr × 80 kg = 1,440 units/hr.
- mL/hr = 1,440 units/hr ÷ 100 units/mL = 14.4 mL/hr.
- 14.4 mL/hr is exact, so no rounding is needed.
Answer 14.4 mL/hr
FAQ
How do you convert mcg/kg/min to mL/hr?
Multiply the order by the weight in kg and by 60 (minutes per hour) to get mcg/hr, convert the bag to mcg per mL, then divide: mL/hr = mcg/hr ÷ mcg/mL.
Why convert the bag from mg to mcg?
The order and the concentration must be in the same unit. Bags are labeled in mg; the order is in mcg, so multiply the bag's mg by 1,000.
Does it handle units/kg/hr heparin orders?
Yes. Choose units as the dose unit and per kg per hour; there is no ×60 step because the order is already per hour.