Dosage rate

The Dosage Rate calculator computes the amount of a drug to be administered in intervals based on a set amount of time to administer a total amount of drug. 

INSTRUCTIONS: Choose units and enter the following:

• (D) Drug amount
• (T) Time span for administration of drug amount
• (I) Interval duration

Dosage per Interval (DpI): The calculator returns the amount of drug to be administered per interval to 

The Math / Science

The formula for the dosage per interval is:

DpI = D * (T/I)

where:

• DpI = Dosage per Interval
• D = Total Drug Amount to be administered over the time span (T).
• T = Time span for total drug amount
• I = Interval duration

Example: A doctor needs a patient to have a 400 milligrams of a heart medicine over the next two days.  The nurse is directed to administer the drug ever four hours.  How much should the dosage be?

DpI = D * (T/I) =  400mg * (2 days /  4 hours) =