Clinical Calculator
Infusion Rate Calculator
Calculate IV infusion rate (mL/hour), infusion time, or drug dose rate for vasoactive medications. Three modes for all clinical scenarios.
Infusion Rate
—
mL/hour
Rate (mL/min)
—
mL/min
Duration (Hours)
—
hours
Duration (h:mm)
—
h : min
Concentration
—
mg/mL
Dose Rate
—
mg/hour
Dose Rate
—
mcg/min
Weight-Based Rate
—
mcg/kg/min
Formulas
Mode A — Volume to Rate
Rate (mL/hr) = Volume (mL) / Time (hours)
Volume — total infusion volume in mL
Time — total infusion duration in hours
Time — total infusion duration in hours
Mode B — Volume to Time
Time (hours) = Volume (mL) / Rate (mL/hr)
Mode C — Drug Dose Rate
mg/hr = (Drug_mg / Bag_mL) × Rate_mL_per_hr
mcg/kg/min = (mg/hr × 1000) / (60 × weight_kg)
mcg/min = mg/hr × 1000 / 60
mcg/min = mg/hr × 1000 / 60
How to Use This Calculator
1
Select your calculation mode: Volume → Rate to find the pump rate, Volume → Time to find infusion duration, or Drug Dose Rate for weight-based vasoactive drug dosing.
2
Enter the required values for your selected mode.
3
Click Calculate to compute the result.
4
Use the result to program your infusion pump or verify current pump settings against the prescriber's order.
Worked Examples
Mode A: 250 mL over 4 hours → Rate = 250 / 4 = 62.5 mL/hour
Mode C: 250 mg dopamine in 250 mL bag, running at 30 mL/hr, 70 kg patient
Concentration = 250/250 = 1 mg/mL
mg/hr = 1 × 30 = 30 mg/hr
mcg/kg/min = (30 × 1000) / (60 × 70) = 30,000 / 4,200 = 7.14 mcg/kg/min
Frequently Asked Questions
Normal IV infusion rates depend on the fluid and clinical indication. Maintenance IV fluids are typically 75–125 mL/hour for adults. Bolus fluids for resuscitation can be administered much faster (e.g., 500–1000 mL over 15–30 minutes). Always follow the prescriber's order.
Dose rate = Concentration (mg/mL) × Rate (mL/hour). First calculate concentration: mg/mL = Drug amount in mg / Bag volume in mL. Then multiply by the pump rate to get mg/hour. Use Mode C (Drug Dose Rate) in this calculator for mg/hour, mcg/min, and mcg/kg/min automatically.
mcg/kg/min (micrograms per kilogram per minute) is used for dosing vasoactive drugs such as dopamine, dobutamine, norepinephrine, and epinephrine. These drugs are titrated by patient weight to achieve precise hemodynamic effects in critical care settings.
Drops per minute = (mL/hour × Drop Factor) / 60. For example, at 120 mL/hour with a 20 gtt/mL set: (120 × 20) / 60 = 40 drops per minute. Use our IV Drip Rate Calculator for a full breakdown.
Infusion rate is expressed in mL/hour and is the setting used on electronic infusion pumps. Drip rate is expressed in drops/minute (gtt/min) and is used when administering IV fluids by gravity with a manual IV administration set, counted against a clock or timing device.