# Infusion Drip Rate Calculator

> Calculate the gravity IV drip rate in drops per minute (gtt/min) from the volume, infusion time and the giving set’s drop factor, with the equivalent mL/h.

Category: Healthcare operations · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/infusion-drip-rate-calculator

For a gravity infusion, drops per minute = volume (mL) × drop factor (gtt/mL) ÷ time (minutes). It supports, and does not replace, clinical judgement and the prescribed order.

Also called: Drops per minute calculator, gtt/min calculator.

## Inputs
- Volume to infuse (unit mL; default 1000)
- Infusion time: hours (unit h; default 8; optional)
- Infusion time: minutes (unit min; default 0; optional)
- Drop factor of the giving set (unit gtt/mL; default 15)

## Results
- Drip rate (rounded)
- Drip rate (unrounded)
- Flow rate
- One drop every

## Formula

```
Drops per minute = Volume (mL) × Drop factor (gtt/mL) ÷ Time (min);  Flow rate (mL/h) = Volume ÷ Time (h)
```

Where:
- Volume: fluid to be infused, in mL
- Drop factor: drops that make 1 mL for this giving set
- Time: prescribed infusion time

## Worked example
1. Time = 8 h × 60 = 480 minutes.
2. Drops per minute = 1,000 × 15 ÷ 480 = 31.25, about 31 gtt/min.
3. Flow rate = 1,000 ÷ 8 = 125 mL/h.

**Result:** 1,000 mL over 8 hours through a 15 gtt/mL set runs at about 31 drops per minute (125 mL/h).

## What the result means

Count drops in the drip chamber for a full minute (or 15 seconds × 4) and adjust the roller clamp to match. Recheck regularly: gravity rates drift as the bag empties or the patient moves.

## Assumptions and limits
- The drop factor is the one printed on the giving set in use.
- The infusion runs at a constant rate for the whole time.
- Gravity drip rates are approximate; use an infusion pump where precise delivery is required.
- The result is only as correct as the prescribed volume and time; it does not check the order.

## Questions

### What drop factor should I use?

Read it from the giving-set packaging. Macro-drip sets are typically 10–20 gtt/mL; micro-drip sets are 60 gtt/mL, where gtt/min equals mL/h.

### Why round to whole drops?

Drops can only be counted whole, so the practical rate is the nearest whole number; the unrounded value is shown too.

## Sources
- [Math for Medication Administration (BCcampus open textbook): IV flow rates](https://opentextbc.ca/nursingnumeracy/chapter/iv-flow-rates/)

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- [IV Flow Rate Calculator](https://calculators.geekmidst.com/calculators/iv-flow-rate-calculator)
- [Medication Days Supply Calculator](https://calculators.geekmidst.com/calculators/medication-days-supply-calculator)
- [Time Calculator](https://calculators.geekmidst.com/calculators/time-calculator)

_This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health._

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/infusion-drip-rate-calculator