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.

Choose what you want to calculate. Only the required inputs will show.
Required. Volume of fluid to be infused.
Required. Total time the infusion runs.
Required. Drops per mL printed on your tubing set.
Required. The prescribed dose rate.
Required.
Required. Drug amount per mL of the prepared solution.

Infusion Rate Calculator Guide

This calculator helps with three common infusion tasks: standard IV pump rates, gravity drip rates, and dose-based medication infusions. Use consistent units, leave only the field you want solved blank, and verify the final setting before administration.

Core Formulas

Calculation Formula Typical Output
IV pump rate
Rate₍mL / hr) = (Volume₍mL)) / (Timeₕᵣ)
 mL/hr
Total volume
Volume₍mL) = Rate₍mL / hr) × Timeₕᵣ
 mL
Infusion time
Timeₕᵣ = (Volume₍mL)) / (Rate₍mL / hr))
 hr
Gravity drip rate from volume and time
gtt / min = (Volume₍mL) × DropFactor₍gtt / mL)) / (Timeₘᵢₙ)
 gtt/min
Gravity drip rate from pump rate
gtt / min = (Rate₍mL / hr) × DropFactor₍gtt / mL)) / (60)
 gtt/min

How to Use Each Mode

Mode Enter Best Use
IV Pump Rate Any two of volume, time, or rate Standard pump programming in mL/hr or mL/min
Gravity Drip Rate Drop factor plus either gtt/min or mL/hr; volume and time are optional 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 Rapid fluid administration
Macrodrip 15 gtt/mL General adult infusions
Macrodrip 20 gtt/mL General fluid delivery
Microdrip 60 gtt/mL Pediatric use or tighter manual control

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.

Concentration₍mg / mL) = (Drug₍mg)) / (Volume₍mL))
Concentration₍mcg / mL) = (Drug₍mg) × 1000) / (Volume₍mL))
Ordered Dose Unit Pump Rate Formula
mcg/kg/min
mL / hr = (Dose₍mcg / kg / min) × Weight₍kg) × 60) / (Concentration₍mcg / mL))
mcg/kg/hr
mL / hr = (Dose₍mcg / kg / hr) × Weight₍kg)) / (Concentration₍mcg / mL))
mg/kg/hr
mL / hr = (Dose₍mg / kg / hr) × Weight₍kg)) / (Concentration₍mg / mL))
mg/hr
mL / hr = (Dose₍mg / hr)) / (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, usually rounded to 31 gtt/min
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 Use kg, not lb

Tip: If you are solving for a missing value in standard infusion mode, enter the two known values and leave only one field blank. For dose-based infusions, calculate or verify the concentration first, then convert the ordered dose to mL/hr.