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IV Flow Rate Calculator

Calculate intravenous infusion flow rate in millilitres per hour and drops per minute.

About IV Flow Rate Calculator

Flow rate in millilitres per hour is used for pumps while drops per minute is used for gravity sets. The drop factor is printed on the giving set packaging and differs between standard and microdrip sets. Using the wrong drop factor changes the delivered rate threefold, which is why the giving set must be confirmed rather than assumed.

Formula

IV Flow Rate

Drops per minute = volume × drop factor ÷ duration in minutes

drop factor
Drops per millilitre for the giving set, commonly 10, 15, 20 or 60
seconds per drop
Used to count manually against a watch

Worked example

With the default values below, IV Flow Rate Calculator returns Flow Rate of 125.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Volume to infuseminimum 0.1 mL
1,000 mL
Infusion durationminimum 0.01 h
8 h
Drop factorminimum 1 drops/mL
20 drops/mL

Results

Flow Rate
125.00 mL/h
Drops per Minute
41.7 drops/min
Seconds Between Drops
1.44 s
Flow Rate
2.0833 mL/min
Infusion Duration
480.0 min

Step by step

  1. 1Values used
  2. 2IV Flow Rate
  3. 3Flow Rate= 125.00 mL/h
  4. 4Drops per Minute= 41.7 drops/min
  5. 5Seconds Between Drops= 1.44 s
  6. 6Flow Rate= 2.0833 mL/min
  7. 7Infusion Duration= 480.0 min

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • This performs arithmetic on figures you supply and does not recommend any drug, dose or route. Medication errors can cause serious harm or death. Always verify every calculation independently, confirm against the prescription and product literature, and follow your institution's double-check procedures. Never self-medicate or alter a prescribed dose.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

This performs arithmetic on figures you supply and does not recommend any drug, dose or route. Medication errors can cause serious harm or death. Always verify every calculation independently, confirm against the prescription and product literature, and follow your institution's double-check procedures. Never self-medicate or alter a prescribed dose.

Frequently Asked Questions

How is IV Flow Rate calculated?

Drops per minute = volume × drop factor ÷ duration in minutes Flow rate in millilitres per hour is used for pumps while drops per minute is used for gravity sets. The drop factor is printed on the giving set packaging and differs between standard and microdrip sets.

Why does IV Flow Rate matter?

Using the wrong drop factor changes the delivered rate threefold, which is why the giving set must be confirmed rather than assumed.

What values do I need to enter?

This calculator takes 3 inputs: Volume to infuse, Infusion duration, Drop factor. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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