mcg/kg/min Infusion Rate Calculator: Dose to mL/h and mL/h to Dose
Convert a weight-based mcg/kg/min order into a pump rate in mL/hour from the patient weight and the bag concentration, or work back from a running mL/h to the dose; also handles mcg/min, mcg/kg/h, mg/kg/h, mg/min, mg/h and ng/kg/min, with a titration table and bag time.
How it works
Concentration (mcg/mL) = drug (mg) × 1,000 ÷ bag (mL) · mL/h = dose (mcg/kg/min) × weight (kg) × 60 ÷ concentration (mcg/mL) · Dose (mcg/kg/min) = mL/h × concentration ÷ (60 × weight) · mcg/kg/h ÷ 60 = mcg/kg/min; mg = 1,000 mcg; ng = 0.001 mcg
Many vasoactive, inotropic and sedative drips are ordered per kilogram per minute, but the pump is set in millilitres per hour, so two conversions are needed. First multiply the dose by the weight to get micrograms per minute; then multiply by 60 for an hour and divide by the bag concentration in mcg/mL. The calculator derives the concentration from the amount of drug in the bag (mg, mcg or g) and the final bag volume, so check it against the admixture label. Switch to "Dose from mL/h" to work backwards from a running rate, for example at handover. Orders are not always written in mcg/kg/min. The dose unit list also covers mcg/min (no weight), mcg/kg/h, mg/kg/h, mg/min, mg/h and ng/kg/min, and the second table restates the dose in each unit. The titration table shows the pump rate for doses around the order, using your titration step or one fifth of the dose. Dose ranges and maximums are drug-specific and are not built in: use the order, the drug library and your institution's protocol, which take precedence.
Worked example
With the defaults, 5 mcg/kg/min for a 70 kg patient with 400 mg in 250 mL: concentration = 400 × 1,000 ÷ 250 = 1,600 mcg/mL; total dose = 5 × 70 = 350 mcg/min; pump rate = 350 × 60 ÷ 1,600 = 21,000 ÷ 1,600 = 13.1 mL/h (13.13 to two decimals), which is 21 mg per hour, and the bag lasts about 19 hours. Working back, 13.1 mL/h on the same bag delivers 4.99 mcg/kg/min.
Sources: Medication calculations: worked mcg/kg/min dopamine examples (SUNY Upstate Medical University) · NIH/NLM DailyMed — drug labeling, concentrations and dosing · Vasopressors: dosing units (mcg/min, mcg/kg/min) and standard concentrations (WikEM)
Frequently asked questions
How do I convert mcg/kg/min to mL/h?
Multiply the dose by the weight and by 60, then divide by the concentration in mcg/mL. For 10 mcg/kg/min, 70 kg and 1,600 mcg/mL: 10 × 70 × 60 ÷ 1,600 = 26.25, programmed as 26.3 mL/h.
Why multiply by 60?
The dose is per minute but the pump runs per hour. Multiplying the per-minute amount by 60 converts it to per hour. Skipping this step is a classic 60-fold error, so always confirm the final unit is mL/h.
How do I get the concentration in mcg/mL?
Multiply the milligrams of drug in the bag by 1,000 to get micrograms, then divide by the bag volume in mL. 400 mg in 250 mL is 400,000 mcg ÷ 250 mL = 1,600 mcg/mL; 4 mg in 250 mL is 16 mcg/mL.
How do I work out the dose from the pump rate?
Reverse the formula: dose (mcg/kg/min) = mL/h × concentration (mcg/mL) ÷ 60 ÷ weight. At 13.1 mL/h with 1,600 mcg/mL and 70 kg: 13.1 × 1,600 ÷ 60 ÷ 70 = 4.99 mcg/kg/min. Choose "Dose from mL/h" above to do this.
What are common drip concentrations?
Typical examples are norepinephrine 8 mg in 500 mL (16 mcg/mL), epinephrine 1 mg in 250 mL (4 mcg/mL), dopamine 400 mg in 250 mL (1,600 mcg/mL) and dobutamine 250 mg in 250 mL (1,000 mcg/mL). Concentrations vary between hospitals and products, so always use the one on your bag label.
What if the order is in mcg/min, mcg/kg/h or ng/kg/min?
Choose that unit in the dose-unit list. mcg/min orders ignore weight; mcg/kg/h is the per-minute dose × 60; ng/kg/min is 1,000 times smaller than mcg/kg/min. Matching the unit on the order exactly prevents 60-fold and 1,000-fold errors.
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Educational estimate only — not medical advice, and no substitute for a clinician, pharmacist or the product label. Vasoactive and sedative infusions are high-alert medications: every dose, concentration and pump rate must be independently double-checked against the actual order, bag label and patient before administration. Institutional protocols, drug libraries and dose limits take precedence over this tool. Do not use it to self-treat or to bypass a double-check policy.