IV Infusion Rate
Calculate IV infusion rate in mL/hr and drops/min, for a fixed dose or a weight-based continuous infusion.
This tool has two modes, depending on how the drug is dosed: a fixed total dose over a set time, or a weight-based continuous infusion rate. See How Calculator Tools Work for the shared layout.
Mode 1 — Fixed dose over a set time
Inputs: total dose (mg), concentration (mg/mL), infusion time (hours), drip set type (macro = 20 drops/mL, or micro = 60 drops/mL).
The tool calculates:
- Volume to infuse = total dose ÷ concentration
- Rate = volume ÷ infusion time (mL/hr)
- Drops per minute = (volume × drip factor) ÷ (infusion time in minutes)
Mode 2 — Weight-based continuous infusion
Inputs: dose per kg per hour (mg or mcg), patient weight (kg), concentration (mg/mL), drip set type.
Used for infusions dosed continuously by weight (e.g. a mcg/kg/min pressor) rather than a fixed total volume — there's no "volume to infuse" or fixed infusion time here, since the infusion runs continuously; the tool gives you the mL/hr rate and drops/min to set the pump or count the drip at.
Drip sets
| Type | Drops per mL |
|---|---|
| Macro | 20 |
| Micro | 60 |
Pick whichever matches the giving set actually in use — using the wrong drip factor when counting drops manually (rather than using a pump) will give you the wrong rate even though the mL/hr figure is unaffected.