MME Calculator

Understanding Morphine Milligram Equivalents (MME)

Morphine Milligram Equivalents (MME) is a standard measure used to compare the potency of different opioid analgesics relative to oral morphine. Because various opioid drugs (such as oxycodone, hydromorphone, and fentanyl) have distinct potencies and pharmacokinetics, calculating the cumulative daily MME provides a unified metric to assess opioid overdose risk and guide safe prescribing practices.

CDC Guidelines and Risk Thresholds

The Centers for Disease Control and Prevention (CDC) Clinical Practice Guideline for Prescribing Opioids establishes key dosage safety thresholds:

• Below 50 MME/day: Lower statistical risk of opioid overdose. Clinicians should use the lowest effective dose when initiating treatment.
• 50 to 89 MME/day: Moderate risk tier. Prescribers should carefully justify increasing dosage, increase clinical monitoring frequency, and offer Naloxone co-prescription.
• 90 MME/day or higher: High risk tier. Dosages at or above 90 MME/day significantly increase fatal overdose risk. Guidelines recommend avoiding escalating to ≥ 90 MME/day without explicit clinical justification or pain specialist consultation.

Common Opioid Conversion Factors

Standard oral MME conversion multipliers established by public health agencies include:

• Codeine: 0.15
• Tramadol: 0.10
• Hydrocodone: 1.0
• Morphine (oral): 1.0
• Oxycodone: 1.5
• Hydromorphone: 4.0
• Oxymorphone: 3.0
• Fentanyl Transdermal Patch: 2.4 MME per mcg/hr
• Methadone: Dose-dependent conversion factor (4.0 for 1-20 mg/day; 8.0 for 21-40 mg/day; 10.0 for 41-60 mg/day; 12.0 for > 60 mg/day)

For other clinical dosing tools, see our Opioid Conversion Calculator and Paracetamol Dosage Calculator.