MED Calculator

Prescription History

What is Morphine Equivalent Dose (MED)?

The MED Calculator is designed to assist in the calculation of patient’s opioid intake. Fill in the mg per day for whichever opioids your patient is taking to automatically calculate the total morphine equivalents per day.

Drug Name mg per day:* Morphine Equivalents:
Fentanyl Transdermal (enter in mcg/hr)

*All doses expressed in mg per day with exception of fentanyl transdermal, which is expressed in mcg per hour


  1. All doses should be in mg/day, except for fentanyl which should be in mcg/hr, before multiplying by the conversion factor.
  2. Equianalgesic dose conversions are only estimates and cannot account for individual variability in genetics and pharmacokinetics.
  3. Do not use the calculated dose in MMEs to determine the doses to use when converting opioid to another; when converting opioids the new opioid is typically dosed at substantially lower than the calculated MME dose to avoid accidental overdose due to incomplete cross-tolerance and individual variability in opioid pharmacokinetics.
  4. Use particular caution with methadone dose conversions because the conversion factor increases at higher doses.
  5. Use particular caution with fentanyl since it is dosed in mcg/hr instead of mg/day, and its absorption is affected by heat and other factors.

For more information, please visit the CDC's website by clicking here.