Works out the millilitres per hour (mL/hr) rate for an infusion pump — or a rate check on a gravity set — from the volume to be infused and the time allowed.
Formula: flow rate (mL/hr) = volume (mL) ÷ time (hours). Set the pump to the prescribed rate; this calculator checks the arithmetic only and does not replace the prescription or your local infusion policy.
How do I calculate an IV flow rate in mL/hr?
Divide the volume to infuse by the time in hours. For example, 500 mL over 4 hours is 500 ÷ 4 = 125 mL/hr. If the time is given in minutes, convert it to hours first (minutes ÷ 60).
Is mL/hr the same as the drip rate?
Not numerically. mL/hr is the volume rate used to program a pump. The drip rate in drops per minute (gtt/min) additionally depends on the giving set's drop factor: gtt/min = mL/hr × drop factor ÷ 60.
What if the prescribed rate and the remaining volume disagree?
Stop and check rather than adjusting on your own: confirm the prescription, the volume already infused and the time elapsed, and follow your local policy for rate changes. This calculator only performs the arithmetic on the numbers entered.