Drops Per Minute Calculator
Calculate the IV drip rate in drops per minute for gravity infusion based on volume, time, and drop factor.
Formula
gtt/min = (Volume (mL) × Drop Factor) ÷ (Time (hr) × 60)
- gtt/min = drops per minute. gtt = guttae (Latin for drops).
- Common drop factors: 10, 15, 20 gtt/mL for macrodrip; 60 gtt/mL for microdrip.
- For pumps, use mL/hr rate directly (no drop factor needed).
1,000 mL over 8 hours, 20 gtt/mL tubing
Inputs
- Total Volume: 1000 mL
- Infusion Time: 8 hours
- Drop Factor (gtt/mL): 20
Rate = (1000 × 20) ÷ (8 × 60) = 20,000 ÷ 480 = 41.7 → 42 gtt/min.
Frequently asked questions
What is a drop factor?
The number of drops that equals 1 mL of fluid, specific to the IV tubing being used. Always check the tubing package.
When do you use microdrip (60 gtt/mL)?
For small fluid volumes, children, elderly patients, or when precise control is needed.
Is this tool for clinical use?
For educational reference only. Always verify calculations using your institution's clinical protocols.
What if the drip rate gives a decimal?
Round to the nearest whole drop. Count drops for 15 seconds and multiply by 4 to verify.