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Nursing dosage calculation tool

IV Drip Rate Calculator

Calculate a gravity IV drip rate in drops per minute (gtt/min) and a pump flow rate in milliliters per hour (mL/hr). The formulas and working appear with each result.

Calculate a rate

Calculator

Enter the volume, time, and tubing drop factor

The calculator updates both rates as you change an input. Use the drop factor printed on the tubing package.

Use decimals for minutes: 30 minutes = 0.5 hour; 45 minutes = 0.75 hour.
Use the drop factor printed on the tubing package.
Pump flow rate
125 mL/hr
1,000 mL ÷ 8 hr; nearest tenth
Gravity drip rate
31 gtt/min
1,000 × 15 ÷ (8 × 60) = 31.25; rounded to a whole drop

For study only. Not for clinical use.

This tool checks arithmetic for practice. It does not select or verify a patient-specific infusion order, tubing, pump setting, or clinical rate. Follow the current order and local policy in patient care.

Formula

How to calculate an IV flow rate and drip rate

Use the same ordered volume and infusion time for both calculations. Convert hours to minutes when calculating drops per minute.

Pump flow ratemL/hr = volume (mL) ÷ time (hr)Divide the total volume in milliliters by the infusion time in hours. The result is in milliliters per hour; this study calculator displays it to the nearest tenth.
Gravity tubinggtt/min = volume × drop factor ÷ time in minutesMultiply the volume in mL by the tubing drop factor in gtt/mL, then divide by the time in minutes. Round the final drops per minute to a whole number.

A drop factor is the number of drops in one mL for gravity tubing. The factor is printed on the tubing package; Open RN describes the factors and whole-drop rounding in its IV infusion by gravity section, and pump flow in its IV infusion by pump section (Ernstmeyer & Christman, CC BY-SA 4.0). The NCBI-hosted Nursing Skills math chapter also explains infusion-rate calculations and drop factors.

Worked example

A 1,000 mL infusion over 8 hours

With tubing marked 15 gtt/mL, the example produces a pump rate and a gravity rate.

  1. 01Calculate the pump flow rate1,000 mL ÷ 8 hr = 125 mL/hr.
  2. 02Convert the time to minutes8 hr × 60 min/hr = 480 min.
  3. 03Calculate drops per minute(1,000 mL × 15 gtt/mL) ÷ 480 min = 31.25 gtt/min; round to 31 gtt/min.

Practice

Try IV drip rate questions

Practice the same calculation with nursing exam-style questions and worked rationales.

IV drip rate calculation practice: gtt/minIV flow rate calculation practice: mL/hrUse the nursing dosage calculator for tablets, liquids and mg/kgAll nursing dosage calculation practice

Last reviewed November 3, 2026.