Calculate mcg/min from infusion concentration and pump rate, solve for mL/hr, or convert mcg/min to mcg/kg/min and back using the dosing weight.
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mcg/min Formula
The calculator converts between an ordered dose and an IV pump rate using the bag concentration. There are five solve targets: delivered dose, pump rate, concentration, weight-based dose, and pump rate from a weight-based order.
Pump rate from mcg/min
Pump rate from mcg/kg/min
Delivered dose from mL/hr
Concentration is calculated from the bag:
- Dose = ordered infusion rate (mcg/min, mg/min, mcg/kg/min, or mg/kg/min)
- Weight = patient body weight in kg (lb is converted at 1 lb = 0.45359237 kg)
- Drug amount = total drug in the bag (mcg, mg, or g)
- Bag volume = total fluid volume (mL or L)
- Concentration = drug per mL of finished IV solution, in mcg/mL
- Rate = pump infusion rate (mL/hr or mL/min)
Assumptions: the bag is fully mixed, the labeled concentration is accurate, and no overfill is accounted for. Doses entered in mg are converted to mcg (× 1000), and grams are converted to mg (× 1000) before the math runs. Always verify the result against the order, the pump library, and your facility’s protocol before titrating.
Select Pump rate for an order in mcg/min, or Weight-based pump rate for an order in mcg/kg/min. Select Delivered dose to check a running pump, Weight-based dose to include the dosing weight, or Concentration to solve drug concentration from a known dose and flow. These are arithmetic checks, not medication orders.
Illustrative IV Concentration Arithmetic
The mixes below are arithmetic examples, not standard preparations or dose recommendations. Use the product labeling, pharmacy-verified final concentration and local protocol. Drug limits depend on indication and patient factors; for example, nitroprusside labeling includes serious toxicity warnings and duration limits. See the full prescribing information rather than treating a range as generally safe.
| Drug | Illustrative amount / final volume | Concentration | Dose guidance |
|---|---|---|---|
| Nitroglycerin | 50 mg / 250 mL | 200 mcg/mL | See current prescribing information |
| Norepinephrine | 4 mg / 1000 mL | 4 mcg/mL | See current prescribing information |
| Dopamine | 400 mg / 250 mL | 1600 mcg/mL | See current prescribing information |
| Dobutamine | 250 mg / 250 mL | 1000 mcg/mL | See current prescribing information |
| Epinephrine | 4 mg / 250 mL | 16 mcg/mL | See current prescribing information |
| Nitroprusside | 50 mg / 250 mL | 200 mcg/mL | See current prescribing information |
Unit Conversion Quick Reference
| From | To | Multiply By |
|---|---|---|
| mg | mcg | 1000 |
| g | mg | 1000 |
| lb | kg | 0.45359237 |
| mL/min | mL/hr | 60 |
| mcg/min | mg/hr | 0.06 |
Worked Examples
Example 1: Nitroglycerin at 10 mcg/min. Bag is 50 mg in 250 mL. Concentration is (50 × 1000) ÷ 250 = 200 mcg/mL. Rate is (10 × 60) ÷ 200 = 3 mL/hr.
Example 2: Norepinephrine at 0.05 mcg/kg/min for a 70 kg patient. Dose in mcg/min is 0.05 × 70 = 3.5 mcg/min. Bag is 4 mg in 1000 mL, so concentration is 4 mcg/mL. Rate is (3.5 × 60) ÷ 4 = 52.5 mL/hr.
Example 3: Pump running at 15 mL/hr of dopamine 400 mg / 250 mL on an 80 kg patient. Concentration is 1600 mcg/mL. Dose is (15 × 1600) ÷ 60 = 400 mcg/min. Per kg: 400 ÷ 80 = 5 mcg/kg/min.
FAQ
Why multiply by 60? The dose is per minute, but pumps run in mL per hour. Multiplying mcg/min by 60 converts to mcg/hr, which then divides cleanly by mcg/mL to give mL/hr.
What if my order is in mg/hr? Convert to mcg/min first: mg/hr ÷ 0.06 = mcg/min. Then select Pump rate and enter that mcg/min value, or select mg/hr as the dose unit.
Does overfill in the IV bag matter? Use the pharmacy-verified total final solution volume or the labeled final concentration. Do not infer concentration from a nominal bag volume when overfill or added drug volume changes the final volume.
Can I use this for pediatric dosing? The math is the same, but pediatric concentrations and dose ranges differ. Confirm with a pediatric reference and your institution’s smart pump library.
How do I include a dosing weight? Select Weight-based dose to calculate mcg/kg/min from the running flow, concentration and required dosing weight. Select Weight-based pump rate for a weight-based order. Use the dosing-weight basis specified by the order or protocol.
