Calculate IV infusion rates in mL/hr or gtt/min from volume, time, drop factor, dose, concentration, and patient weight for pump or gravity drips.

Optional settings

Infusion Rate Calculator Guide

This calculator supports pump, gravity, weight-based, fixed-dose and medication-units arithmetic. Choose the value to solve for, enter the displayed known values and verify the prescription, preparation, units and final setting independently. It does not determine a safe dose or replace local clinical protocols.

Core Formulas

Calculation Formula Typical Output
IV pump rate Pump rate (mL/h) = volume (mL) / time (h) mL/hr
Total volume Volume (mL) = pump rate (mL/h) × time (h) mL
Infusion time Time (h) = volume (mL) / pump rate (mL/h) hr
Gravity drip rate from volume and time Drip rate (gtt/min) = volume (mL) × drop factor (gtt/mL) / time (min) gtt/min
Gravity drip rate from pump rate Drip rate (gtt/min) = pump rate (mL/h) × drop factor (gtt/mL) / 60 gtt/min

How to Use Each Mode

Mode Enter Best Use
IV Pump Rate The two known values displayed for the selected solve Volume, time and pump-rate arithmetic in mL/h or L/h
Gravity Drip Rate The displayed combination of volume, time, pump rate, drip rate and tubing drop factor Manual flow control with drip tubing
Dose-Based Infusion Drug concentration, ordered dose, and patient weight when required Weight-based or fixed-dose medication infusions

Drop Factor Reference

Tubing Type Drop Factor Common Use
Macrodrip 10 gtt/mL Example calibration; verify the giving-set label
Macrodrip 15 gtt/mL Example calibration; verify the giving-set label
Macrodrip 20 gtt/mL Example calibration; verify the giving-set label
Microdrip 60 gtt/mL Example calibration; follow the prescribed method and local protocol

Dose-Based Infusion Setup

For medication infusions, first determine the concentration in the bag or syringe, then convert the ordered dose into a pump rate.

Concentrationmg / mL = (Drugmg) / (VolumemL)
Concentrationmcg / mL = (Drugmg × 1000) / (VolumemL)
Ordered Dose Unit Pump Rate Formula
mcg/kg/min Pump rate (mL/h) = dose (mcg/kg/min) × weight (kg) × 60 / concentration (mcg/mL)
mcg/kg/hr Pump rate (mL/h) = dose (mcg/kg/h) × weight (kg) / concentration (mcg/mL)
mg/kg/hr Pump rate (mL/h) = dose (mg/kg/h) × weight (kg) / concentration (mg/mL)
mg/hr Pump rate (mL/h) = dose (mg/h) / concentration (mg/mL)

Quick Unit Conversions

Conversion Value
Hours to minutes 1 hr = 60 min
Liters to milliliters 1 L = 1000 mL
Milligrams to micrograms 1 mg = 1000 mcg

Examples

Scenario Setup Result
Standard IV fluid 1000 mL over 8 hr 125 mL/hr
Gravity infusion 500 mL over 4 hr with 15 gtt/mL tubing 31.25 gtt/min exact; 31 gtt/min by nearest-whole-drop rounding, subject to clinical policy
Fixed-dose medication 400 mg in 250 mL, ordered at 8 mg/hr 5 mL/hr
Weight-based infusion 250 mg in 250 mL, 70 kg patient, 5 mcg/kg/min 21 mL/hr

Common Mistakes to Avoid

  • Mixing hours and minutes in the same calculation.
  • Using the wrong drop factor for the tubing set.
  • Forgetting to convert mg to mcg for orders written in micrograms.
  • Entering total drug amount without dividing by bag volume to get concentration.
  • Failing to round manual drip rates to whole drops per minute.
  • Programming a pump in mL/min when the intended unit is mL/hr.

Input Checklist

Field What It Represents Check Before Calculating
Volume Total fluid to infuse Confirm mL vs L
Time Total infusion duration Confirm minutes vs hours
Rate Pump or manual flow rate Confirm mL/hr, mL/min, or gtt/min
Drop Factor Tubing calibration Match the tubing package
Concentration Drug amount per mL Use the prepared bag or syringe concentration
Patient Weight Body weight for dose-based orders Select kg or lb correctly; the calculator converts lb to kg

Tip: Select the quantity to solve, then enter all displayed inputs. For medication infusions, verify the prepared concentration using final total solution volume. Medication units are drug-specific and are not interchangeable with mg or mcg. Follow local protocols and independently check high-risk infusions.