PO Dose Calculator: Solid Forms

Dose Formula: Solids

  • O = Dose ordered
  • A = Dose available
It doesn't matter what type of units are used in this formula.  You can figure out how many grams to give or how many milligrams to give, micrograms, units, grains, etc.  Remember to be consistent in basic mode (e.g., don't mix milligrams with grams).


1. Give 70 milligrams (mg) of Lasix® (furosemide) PO now.  Pharmacy has sent a package of 20-milligram Lasix® tablets.  How many tablets will you give?  Using the formula:

  • dose ordered = 70 mg
  • dose available = 20 mg tablets
70 mg 20 mg

The answer is 3.5. You would give 3 and ½ tablets from the package pharmacy sent.

2. Here's another example.  Give 12.5 milligrams of Capoten® (captopril) PO.  Pharmacy has sent a 50 milligram Capoten®  tablet.  How much of the tablet will be given?  Using the formula:

  • dose ordered = 12.5 mg
  • dose available = 50 mg tablet
12.5 mg 50 mg

The answer is 0.25. You would give ¼ of the tablet.

Certain medications are not intended to be portioned.  Please consult the pharmacist.