Many critical-care drugs are ordered as a dose per kilogram per minute but pumps run in mL per hour. Errors in this conversion are a common cause of serious medication incidents, so double-checking with a second person is standard practice.
How to use the Drip Rate Calculator
- Ordered dose
- Dose unit
- Weight
- Drug in the bag (mg, or units)
- Bag volume
- Drop factor (if gravity)
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the ordered dose, its units and the bag preparation. This tool checks arithmetic only – always follow your local protocol and the prescriber’s order.
Inputs explained
| Field | What to enter |
|---|---|
| Ordered dose | A number |
| Dose unit | Choose one: mg per hour, mcg per kg per minute, mg per kg per hour, units per hour … |
| Weight | Units: kg, lb, st, g |
| Drug in the bag (mg, or units) | A number |
| Bag volume | Units: mL, L, fl oz |
| Drop factor (if gravity) | Choose one: 60 gtt/mL, 20 gtt/mL, 15 gtt/mL, 10 gtt/mL |
What each result means
- Concentration = [Drug in the bag (mg, or units)]÷[Bag volume]
- Infusion rate = [Dose per hour]÷[Concentration]
- Drip rate = [Infusion rate]×[Drop factor (if gravity)]÷60
Example values
How the main result changes when Ordered dose changes and everything else stays at the example values above:
| Ordered dose | Infusion rate (mL/h) |
|---|---|
| 2.5 | 6.6 |
| 3.75 | 9.8 |
| 5 | 13.1 |
| 6.25 | 16.4 |
| 7.5 | 19.7 |
| 10 | 26.3 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Concentration = drug amount ÷ bag volume
Rate (mL/h) = dose per hour ÷ concentration
Weight-based: dose per hour = dose × weight (× 60 if per minute)
Worked example
Inputs — Ordered dose: 5; Dose unit: mcg per kg per minute; Weight: 70 kg; Drug in the bag (mg, or units): 400; Bag volume: 250 mL; Drop factor (if gravity): 60 gtt/mL.
Results — Concentration = 1.6 mg (or units)/mL; Dose per hour = 21 mg (or units)/h; Infusion rate = 13.1 mL/h; Drip rate = 13 drops/min.
Key terms
- mcg/kg/min
- Micrograms per kilogram of body weight per minute.
Frequently asked questions
How do I convert mcg/kg/min to mL/h?
Multiply the dose by weight and 60, divide by 1,000 for mg, then divide by the concentration in mg/mL.
Why use a pump?
Pumps are much more accurate than gravity drips for potent drugs.
Should infusion calculations be double-checked?
Yes – independent double-checks are recommended for high-alert medicines.