mL/hr + Drop Factor to Drops per Minute
Convert infusion rate (mL/hr) and IV tubing drop factor to drip rate (gtt/min) for gravity IV infusions.
Calculator
Educational use only. Always count actual drops at bedside and verify against calculated rate before administration.
How it works
This calculator converts a known mL/hr infusion rate to the equivalent drip rate in drops per minute using the drop factor of the IV tubing. Multiply mL/hr by drop factor, then divide by 60 to get gtt/min. The result tells you how many drops per minute to set on a gravity infusion.
Formula
Worked Examples
Example 1: 125 mL/hr with 20 gtt/mL tubing
gtt/min = (125 × 20) ÷ 60
gtt/min = 2500 ÷ 60 = 41.67
Round to 42 gtt/min
Example 2: 50 mL/hr with 60 gtt/mL (microdrip)
gtt/min = (50 × 60) ÷ 60
gtt/min = 3000 ÷ 60 = 50
Example 3: 200 mL/hr with 10 gtt/mL (blood tubing)
gtt/min = (200 × 10) ÷ 60
gtt/min = 2000 ÷ 60 = 33.33
Round to 33 gtt/min
When This Calculator Is Used
- •Setting up gravity infusions when pump is unavailable
- •Converting pump mL/hr settings to gtt/min for manual gravity infusions
- •Resource-limited or emergency settings requiring bedside drop counting
- •Verifying gravity drip rate calculations in clinical practice
- •Training nurses and students on drop factor conversions
Clinical safety note: Always verify the drop factor on your IV tubing package before calculating. Count actual drops at the bedside to confirm your calculated rate. Adjust the roller clamp if observed and calculated rates differ.
Related Calculators
Frequently Asked Questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.
References & Sources
This calculator uses established IV therapy and gravity infusion standards from authoritative medical and nursing sources worldwide.
Manufacturer Reference
Calculating Flow Rates — BD (Becton, Dickinson and Company) [PDF, p.1]
Shows mL/hr from volume and time and gravity drops/min calculation steps (supports rearrangements and conversions).
View PDF ↗Australia Resources
Drug Calculations — Flinders University [PDF, p.1]
Includes volume/rate/time relationships used for IV calculations.
View PDF ↗Drops per minute (DPM) – Worksheet — University of South Australia [PDF, p.2–3]
Shows time = volume ÷ rate and drip/infusion conversions with worked examples.
View PDF ↗United Kingdom Resources
Intravenous Drug and Fluid Administration Training – Calculation Practice Papers — Gloucestershire Hospitals NHS Foundation Trust [PDF, p.5]
Step method linking mL/hr, mL/min, and drops/min plus rounding guidance.
View PDF ↗Canada Resources
Calculating Drop Factor with Gravity IV Infusions — London Health Sciences Centre [PDF, p.1]
mL/hr ÷ 60 × drop factor = drops/min (supports gtt/min ↔ mL/hr conversions).
View PDF ↗