Desired Over Have Formula Calculator: Universal Formula (Toney Butler)
This Drug Dose Calculator allows you to calculate adult medication dose using the desired over have formula, also known as Universal Formula.
Here is the dose calculator using this desired over have formula.
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 (e.g., don’t mix milligrams with grams).
Desired Over Have Formula
In the Desired Over Have Formula (or “universal formula”), the desired amount (D) is the dose prescribed and the amount on hand (H) or the amount you “have” is the available dose or concentration. The quantity (Q) is the form and amount in which the drug is supplied (i.e. tablet, capsule, liquid).
Formula Equation
Universal Formula (Desired Over Have Formula)
To calculate the dose, take the desired amount and divide it by the amount on hand, then multiply it by the quantity like this, D/H×Q=Dose.
Calculation Examples
The physician orders Cephalexin 750 mg P.O. every 12 hours. How many tablets should be administered per dose?
Answer:
- D=750,
- H=250,
- Q=1
D/H×Q=Dose
750/250×1 = 3Tablets
General Tips
- Check that your answer makes sense clinically.
- Triple check your work.
- Ask a colleague or pharmacist to check your work.
- Know general therapeutic drug doses for commonly administered medications.
How to Use Desired Over Have Calculator?
- Enter desired dose.
- Enter amount of medication on hand and Available Quantity.
- Click on “Calculate” button.
- The calculator will display the desired drug dose below.
Click here to calculate your Body Mass Index (BMI).
To calculate your Body Surface Are (BSA) click here.
Check our resources if you are interested in different measurements related to Child’s Drug Dose:
- Use the Clarks rule for the Weight-Based pediatric drug dose calculator.
- Utilize the Pediatric BSA Dose Calculator.
- Child Drug Dose Calculators based on age using: