# Calculate IV rate as gtt/min

## Formulas

To calculate rate as drops/minute (gtt/min) using minutes:

$\frac{V×C}{M}$
• V = Volume
• C = Calibration
• M = Minutes

To calculate rate as gtt/min using hours:

$\frac{V×C}{\left(H×\mathrm{60 min}\right)}$
• V = Volume
• C = Calibration
• H = Hours

To convert milliliters/hour (mL/hr) to gtt/min:

$\frac{R×C}{\mathrm{60 min}}$
• R = Rate
• C = Calibration

## Examples

1. Give a 50 milliliter (mL) IVPB over 30 minutes using IV tubing with a calibration of 10 drops/milliliter (gtt/mL).  How many drops per minute should this IVPB be set for?

• Volume = 50 mL
• Calibration = 10
• Minutes = 30 min
$\frac{\mathrm{50 mL}×\mathrm{10}}{\mathrm{30 min}}$

The answer is 16.7 or 70 gtt/min.

2. Using IV tubing alone (calibrated at 60 gtt/mL), prepare an IV to infuse 1 liter over 8 hours.  How many drops per minute should the IV be set for?

• Volume = 1000 mL
• Calibration = 60
• Hours = 8
$\frac{\mathrm{1000 mL}×\mathrm{60}}{\left(8×\mathrm{60 min}\right)}$

$\frac{\mathrm{125}×\mathrm{10}}{\mathrm{60 min}}$