What is the IV drip rate?
Enter the volume, the infusion time, and the drop factor of the giving set to get the IV drip rate in drops per minute and the same rate in mL per hour. For information only. This is not medical advice or a diagnosis. Do not use it to make treatment decisions without a clinician. No licensed clinician has reviewed this page.
- Drip rate (gtt/min)
- 41.67
1,000 mL over 8 h with a 20 gtt/mL set runs at 41.67 drops a minute (125 mL/h).
- Drops per minute, whole
- 42
- Pump rate (mL/h)
- 125
Drip rate (gtt/min): 41.67. 1,000 mL over 8 h with a 20 gtt/mL set runs at 41.67 drops a minute (125 mL/h).
Drops per minute
This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use
How to calculate
Works out an IV drip rate in drops per minute from the volume, the infusion time, and the drop factor of the giving set, with the same infusion as a pump rate in mL per hour.
Example with the default inputs (Volume to infuse 1,000 mL, Infusion time 8 h, Drop factor (gtt/mL) 20): 1,000 mL over 8 h with a 20 gtt/mL set runs at 41.67 drops a minute (125 mL/h).
Method: Drops per minute = volume (mL) × drop factor (gtt/mL) ÷ time (minutes). mL per hour = volume (mL) ÷ time (hours).
- A gravity infusion at a steady rate; the drop factor is the one printed on the giving set.
- The page works out the rate for an order a clinician has written. It does not choose a fluid, a volume, or a time.
- The rate is worked from the exact typed values and rounded once: 2 decimals, and to a whole drop with halves up.
Worked examples
Each example is checked against the calculator on every build.
- Volume to infuse 1,000 mL, Infusion time 8 h, Drop factor (gtt/mL) 20 gives Drip rate (gtt/min) 41.666667, Drops per minute, whole 42, Pump rate (mL/h) 125.Source: Open RN Nursing Skills (Ernstmeyer et al.), 5.14: gtt/min = mL × gtt/mL ÷ min: 1000 × 20 ÷ 480 = 41.67
- Volume to infuse 100 mL, Infusion time 0.5 h, Drop factor (gtt/mL) 15 gives Drip rate (gtt/min) 50, Drops per minute, whole 50, Pump rate (mL/h) 200.
- Volume to infuse 250 mL, Infusion time 2 h, Drop factor (gtt/mL) 60 gives Drip rate (gtt/min) 125, Drops per minute, whole 125, Pump rate (mL/h) 125.
- Volume to infuse 500 mL, Infusion time 4 h, Drop factor (gtt/mL) 10 gives Drip rate (gtt/min) 20.833333, Drops per minute, whole 21, Pump rate (mL/h) 125.
- Volume to infuse 50 mL, Infusion time 0.6667 h, Drop factor (gtt/mL) 15 gives Drip rate (gtt/min) 18.75, Drops per minute, whole 19, Pump rate (mL/h) 75.
Medical disclaimer
This calculator is for information and education only. It is not medical advice, and its result is not a diagnosis. Do not use it to start, stop, or change a treatment without a clinician who knows your health history. No licensed clinician has reviewed this page. This site's editors checked the formulas and worked examples against published sources. If you think you have a medical emergency, call your local emergency number.
When this does not apply. The formula is for a gravity drip at a steady rate. It does not apply to an infusion pump that is set in mL per hour (use the mL/h result), to syringe drivers, or to drugs dosed by weight per minute, which need a separate dose calculation.
How the rate is worked out
- Volume in mL: a value typed in L is × 1,000.
- Time in minutes: a value typed in hours is × 60.
- Drops per minute = volume (mL) × drop factor (drops per mL) ÷ time (minutes).
- mL per hour = volume (mL) ÷ time (hours) = volume × 60 ÷ time (minutes).
The arithmetic runs on the exact typed decimals and is rounded once at the end: drops per minute and mL per hour to 2 decimals, and the whole-drop rate to the nearest whole number, halves up (18.75 becomes 19).
Inputs: volume 1 mL to 10 L, time 1 minute to 72 hours, drop factor a whole number from 1 to 100. A rate under 1 drop a minute gives no answer, because it is too slow to count.
Worked examples by hand
1,000 mL over 8 hours, 20 drops/mL. 8 h = 480 min. 1,000 × 20 ÷ 480 = 41.67 drops a minute, 42 whole drops. 1,000 ÷ 8 = 125 mL/h.
100 mL over 30 minutes, 15 drops/mL. 100 × 15 ÷ 30 = 50 drops a minute. 100 ÷ 0.5 h = 200 mL/h.
250 mL over 2 hours, 60 drops/mL (microdrip). 250 × 60 ÷ 120 = 125 drops a minute = 125 mL/h.
500 mL over 4 hours, 10 drops/mL. 500 × 10 ÷ 240 = 20.83 drops a minute, 21 whole drops; 125 mL/h.
50 mL over 40 minutes, 15 drops/mL. 50 × 15 ÷ 40 = 18.75 drops a minute; the half rounds up to 19. 50 × 60 ÷ 40 = 75 mL/h.
Other questions people ask
How do you work out a drip rate?
Multiply the volume in mL by the drop factor of the giving set (drops per mL), then divide by the time in minutes. For 1,000 mL over 8 hours with a 20 drops/mL set: 1,000 × 20 ÷ 480 = 41.67, about 42 drops a minute.
What is a drop factor?
The number of drops that make 1 mL with a given giving set. It is printed on the package. Macrodrip sets are usually 10, 15, or 20 drops per mL; microdrip sets are 60 drops per mL.
Why do drops per minute equal mL per hour with a microdrip set?
A 60 drops/mL set gives 60 drops for each mL, and an hour has 60 minutes, so the two 60s cancel: drops per minute = mL per hour.
Should I round the drip rate?
Drops can only be counted whole, so the page also shows the rate rounded to the nearest whole drop, halves up. The exact rate is shown to 2 decimals.
What is mL per hour used for?
An infusion pump is set in mL per hour. The page divides the volume by the time in hours to give that rate for the same order.
Does the page choose a fluid or a rate?
No. It only does the arithmetic for an order that a clinician has written: the volume, the time, and the set in use.