EMS Registry Ready

IV drip rate calculator

Work out the rate for a pump in mL/hr and for a gravity set in drops a minute. Every step of the math is shown, so you can check your own work and do it by hand on the exam.

mL

Enter the numbers above and the rate appears here.

Use it to check your math, not in place of your protocol, your medical direction or your pump's drug library.

The formulas

For a volume run over a set time:

mL/hr = volume (mL) ÷ time (hours)
gtt/min = volume (mL) × drop factor (gtt/mL) ÷ time (minutes)

For a drip ordered as a dose, first find how much drug is in each mL, then how many mL a minute the dose needs:

concentration = drug in the bag ÷ bag volume (mL)
mL/min = dose per minute ÷ concentration
mL/hr = mL/min × 60 · gtt/min = mL/min × drop factor

The drop factor is printed on the tubing package: 10, 15 or 20 gtt/mL for a macrodrip set, 60 gtt/mL for a microdrip set. On a microdrip set, gtt/min and mL/hr are the same number.

Worked examples

1,000 mL over 8 hours on a 15 gtt/mL set

125 mL/hr on a pump, or 31 gtt/min by gravity: about 8 drops every 15 seconds.

  1. Time in minutes: 8 hr × 60 = 480 min
  2. Volume per minute: 1,000 mL ÷ 480 min = 2.08 mL/min
  3. Pump rate: 2.08 mL/min × 60 = 125 mL/hr
  4. Drip rate: 2.08 mL/min × 15 gtt/mL = 31.25 gtt/min

100 mL over 30 minutes on a 10 gtt/mL set

200 mL/hr on a pump, or 33 gtt/min by gravity.

  1. Volume per minute: 100 mL ÷ 30 min = 3.33 mL/min
  2. Pump rate: 3.33 mL/min × 60 = 200 mL/hr
  3. Drip rate: 3.33 mL/min × 10 gtt/mL = 33.33 gtt/min

A dose in mcg/kg/min: 400 mg in 250 mL at 5 mcg/kg/min, 80 kg patient, microdrip set

15 mL/hr, or 15 gtt/min on a 60 gtt/mL set. These numbers show the math only; they are not a dose for any drug.

  1. Concentration: 400 mg is 400,000 mcg. 400,000 mcg ÷ 250 mL = 1,600 mcg/mL
  2. Dose for this patient: 5 mcg/kg/min × 80 kg = 400 mcg/min
  3. Volume per minute: 400 mcg/min ÷ 1,600 mcg/mL = 0.25 mL/min
  4. Pump rate: 0.25 mL/min × 60 = 15 mL/hr
  5. Drip rate: 0.25 mL/min × 60 gtt/mL = 15 gtt/min

Want practice? Med math in the app gives you new drip and dose problems, graded, with the working shown. It's in Drug Cards for AEMT and Paramedic, and you can try 5 problems a day free.

Try med math