# Nursing Math Medication and IV Formulas

## Dose Formula: Solids

$\frac{O}{A}$
• O = Dose ordered
• A = Dose available

## Dose Formula: PO Liquids, Injectables, Dose → mL

$\frac{O×V}{A}$
• O = Dose ordered
• V = Volume of dose available
• A = Dose available

## Calculate IV rate as mL/hr using hours:

$\frac{V}{H}$
• V = Volume
• H = Hours

## Calculate IV rate as mL/hr using minutes:

$\frac{V×\mathrm{60 min}}{M}$
• V = Volume
• M = Minutes

## mcg/min → mL/hr

First, convert micrograms per minute (mcg/min) to milligrams per hour (mg/hr).

$\frac{D×60 min}{1000 mcg}$
• D = Dose (mcg)

Then use the dosage formula to calculate rate.

$\frac{O×V}{A}$
• O = Dose ordered
• V = Volume of dose available
• A = Dose available

## mcg/kg/min → mL/hr

First, convert micrograms per kilograms per minute (mcg/kg/min) to milligrams per hour (mg/hr).

$\frac{D×W×\mathrm{60 min}}{1000 mcg}$
• D = Dose (mcg)
• W = Weight (kg)

Then use the dosage formula to calculate rate.

$\frac{O×V}{A}$
• O = Dose ordered
• V = Volume of dose available
• A = Dose available

## Calculate Time in Hours with IV pump

Use the basic time formula with an IV pump to calculate hours.

$\frac{V}{R}$
• V = Volume
• R = Rate

## Calculate Time in Hours without IV pump

Drops/minute (gtt/min) must be converted into hours when using calibrated tubing without a pump.

$\frac{V×C}{\left(G×\mathrm{60 min}\right)}$
• V = Volume
• C = IV tubing calibration
• G = gtt/min

## 1 × Dose, dose/hr ← mL/hr

$\frac{R×A}{V}$
• R = Rate
• A = Dose available
• V = Volume of dose available

## mcg/min ← mL/hr

First, determine the dosage given milligrams/hour (mg/hr).

$\frac{R×A}{V}$
• R = Rate
• A = Dose available
• V = Volume of dose available

Next, convert dosage from mg/hr to microgram/minute (mcg/min).

$\frac{D×\mathrm{1000 mg}}{60 min}$
• D = Dose (mg)

## mcg/kg/min ← mL

First, determine the dosage given milligrams/hour (mg/hr).

$\frac{R×A}{V}$
• R = Rate
• A = Dose available
• V = Volume of dose available

Next, convert dosage from mg/hr to microgram/kilogram/minute (mcg/kg/min).

$\frac{D×\mathrm{1000 mg}}{\left(60 min×W\right)}$
• D = Dose (mg)
• W = Weight in kilograms (kg)