IV & Fluid Management
Intravenous infusion and drip-rate calculators for mL/hr, gtt/min, time to finish, and volume–time–rate conversions.
mL/hr to gtt/min
Convert mL/hour infusion rate to drops per minute
Volume & Time to gtt/min
Calculate drip rate from total volume and infusion time
gtt/min to mL/hr
Convert drops per minute back to mL per hour
15-Second Count to Rate
Calculate infusion rate using 15-second drop count method
mL/hr + Drop Factor to Drops/min
Calculate drops per minute from infusion rate and drop factor
mL/hr to Time to Finish
Calculate remaining infusion time from rate and volume
Volume + Rate to Infusion Time
Calculate total infusion duration from volume and rate
How IV & Fluid Management Calculations Work
IV and fluid management calculations control how fast fluids or medications are delivered through an intravenous line. These calculations ensure patients receive the correct amount of fluid over the correct period of time, whether using gravity drip sets or infusion pumps.
The core inputs are volume (mL), time (hours or minutes), rate (mL/hr), and for manual gravity infusions, drop factor (gtt/mL). Accurate calculations and unit conversions are critical; always double-check values and confirm local protocols before administration.
Common IV & Fluid Management Calculations Explained
Infusion rate (mL/hr)
Used for setting or checking infusion pump rates based on total volume and time.
Example question:
A bag has 1,000 mL to run over 8 hours. What infusion rate (mL/hr) should be set?
Worked example:
Total volume = 1,000 mL
Time = 8 hours
mL/hr = 1,000 ÷ 8 = 125
Result: 125 mL/hr
Tip: Volume ÷ hours = mL per hour.
Drip rate (gtt/min)
Used for gravity infusions; converts mL/hr into drops per minute using the giving set drop factor (gtt/mL).
Example question:
An infusion runs at 120 mL/hr. The giving set is 20 gtt/mL. What is the drip rate (gtt/min)?
Worked example:
mL/min = 120 ÷ 60 = 2 mL/min
gtt/min = 2 × 20 = 40 gtt/min
Result: 40 gtt/min
Tip: Divide by 60 first, then multiply by the drop factor.
Time to finish an infusion (hours)
Estimates how long is left using remaining volume and current rate—useful during routine checks and handover.
Example question:
There is 600 mL remaining and the infusion is running at 150 mL/hr. How long until it finishes?
Worked example:
Remaining volume = 600 mL
Rate = 150 mL/hr
Time = 600 ÷ 150 = 4
Result: 4 hours
Tip: Remaining ÷ rate = hours left.
When These Calculators Are Used
- •Setting infusion pump rates from ordered volume and time (mL/hr)
- •Converting pump rates to gravity drip rates for manual counting (gtt/min)
- •Estimating time remaining to finish during observations and handover
- •Adjusting rates when the order changes (time, volume, or target rate)
- •Double-checking calculations in busy/high-risk situations
Clinical safety note: Always confirm the order, delivery method (pump vs gravity), drop factor (gtt/mL), and local protocols. These calculators support calculation checking but do not replace professional judgement. Examples on this page are for calculation practice only.
Frequently Asked Questions
Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.