Printed on 3/17/2026
For informational purposes only. This is not medical advice.
This calculator converts opioid doses to morphine milligram equivalents (MME) using CDC conversion factors. MME standardizes opioid prescribing by providing a common unit to compare potency across different opioids. The CDC recommends caution at ≥50 MME/day and avoiding or carefully justifying ≥90 MME/day due to significantly increased overdose risk. Renal impairment decreases opioid clearance and increases toxicity risk — monitor with [eGFR Calculator](/tools/egfr-calculator) and [Creatinine Clearance](/tools/creatinine-clearance). Screen for co-occurring depression with [PHQ-9](/tools/phq9) and alcohol misuse with [AUDIT](/tools/audit) in patients on chronic opioids.
Formula: MME = Daily Dose × Conversion Factor
Choose the specific opioid from the list. Each opioid has a different potency relative to morphine, reflected in its conversion factor.
Input the total daily dose in mg (or mcg/hr for fentanyl patches). If the patient takes multiple doses per day, sum them. If taking multiple opioids, calculate each separately.
The calculator multiplies the dose by the conversion factor to show total daily MME. Compare against CDC thresholds: <50 MME (lower risk), 50–89 MME (caution), ≥90 MME (high risk).
Pain management, primary care
Calculate total MME for patients on chronic opioid therapy to assess overdose risk, guide dosing decisions, and document compliance with prescribing guidelines.
Pharmacists, PDMP staff
PDMPs calculate and display MME to flag high-risk prescribing patterns. Pharmacists use MME to verify doses are within reasonable limits before dispensing.
Emergency physicians
Assess the opioid burden of patients presenting with overdose, altered mental status, or requesting refills. High MME suggests need for careful evaluation.
Quality officers, administrators
Track prescriber-level MME metrics as part of opioid stewardship programs. Many institutions set thresholds that trigger pharmacist review or provider notification.
All opioid prescribers
CDC recommends naloxone co-prescribing for patients on ≥50 MME/day, those with respiratory conditions, or those taking benzodiazepines concurrently.
Palliative care, pain specialists
When rotating from one opioid to another, MME provides a common reference point. Always apply a dose reduction (typically 25–50%) from the calculated equianalgesic dose.
Do NOT use MME to directly convert between opioids. When rotating opioids, apply a 25–50% dose reduction from the calculated equianalgesic dose to account for incomplete cross-tolerance.
Methadone's conversion factor increases with dose (4× for 1–20mg, 8× for 21–40mg, 10× for 41–60mg, 12× for >60mg). Its long, variable half-life makes it high-risk. Specialist consultation is recommended.
If a patient takes multiple opioids (e.g., long-acting oxycodone + breakthrough hydrocodone), calculate MME for each and sum them for the total daily MME.
Fentanyl transdermal patches are dosed in mcg/hr. The conversion to MME varies by source but is approximately 2.4× (e.g., 25 mcg/hr patch ≈ 60 MME/day).
Concurrent benzodiazepine use dramatically increases overdose risk. CDC guidelines recommend avoiding concurrent prescribing when possible, and if unavoidable, keeping opioid doses as low as possible.
CDC recommends offering naloxone to patients on ≥50 MME/day, those with respiratory conditions (sleep apnea, COPD), or those taking benzodiazepines. Many states require co-prescribing at certain MME thresholds.
A patient stable on 100 MME/day for years has different risk than an opioid-naive patient suddenly prescribed 100 MME. Tolerance provides some protection, but high doses remain risky.
If a patient has both scheduled and PRN opioids, estimate the actual daily intake including PRN use. A patient prescribed 60 MME scheduled + 30 MME PRN and using all of it is at 90 MME/day.
When prescribing >50 MME/day, document the clinical rationale, the risk-benefit discussion with the patient, and the safeguards in place (naloxone, monitoring, urine drug screens, PDMP checks).
CDC 2022 guidelines apply to chronic pain in outpatients. Acute pain, cancer pain, palliative care, and end-of-life care have different considerations. Don't withhold appropriate pain treatment based solely on MME thresholds.
This calculator uses conversion factors from the CDC Clinical Practice Guideline for Prescribing Opioids for Pain (2022). The 50/90 MME thresholds are based on epidemiological studies showing dose-dependent increases in overdose mortality. The guidelines are endorsed by major medical organizations and inform state prescribing laws and PDMP alert systems.
The morphine milligram equivalent (MME) result represents the total daily opioid exposure expressed in standardized morphine-equivalent units. Per CDC guidelines, prescribers should exercise caution at doses of 50 MME/day or greater, as the risk of opioid overdose increases substantially at this level. At 90 MME/day or above, the risk of fatal overdose is significantly elevated, and the CDC recommends avoiding or carefully justifying doses in this range while implementing additional safeguards such as prescribing naloxone.
Below 50 MME/day is considered standard risk, though all opioid prescribing carries inherent risks including dependence, tolerance, respiratory depression, and overdose. The MME value helps clinicians and patients understand the relative potency of different opioid prescriptions and track total opioid burden, especially when patients receive multiple opioid medications or formulations.
Calculate MME whenever prescribing, reviewing, or adjusting opioid medications for chronic pain management. It is particularly important during initial opioid prescribing, dose escalation, formulary changes (switching between opioids), and when evaluating patients receiving opioids from multiple providers. Many states and institutions now require MME calculation as part of opioid prescribing protocols.
MME is also used in prescription drug monitoring programs (PDMPs) to flag high-risk prescribing patterns, in quality improvement initiatives to reduce opioid-related harm, and in research studies comparing opioid utilization. Pharmacists use it during dispensing review to verify that total daily doses are within acceptable limits and to identify patients who may benefit from naloxone co-prescribing.
Opioid conversion factors are population-level approximations and do not account for individual patient variability. Factors such as age, organ function (hepatic and renal), genetic polymorphisms in opioid metabolism (CYP2D6 variants), drug interactions, prior opioid exposure, and tolerance all affect how a patient responds to a given dose. The MME value should guide — not replace — clinical judgment.
Methadone conversion is particularly complex because its conversion factor is not linear — it increases with dose due to methadone's long and variable half-life, lipophilicity, and NMDA receptor activity. The factor used in this calculator applies to a specific dose range and may significantly underestimate MME at higher methadone doses. Methadone conversion should involve specialist consultation.
MME calculations should not be used for direct dose conversion between opioids (opioid rotation). When switching from one opioid to another, clinicians typically apply a 25–50% dose reduction from the calculated equianalgesic dose to account for incomplete cross-tolerance. Using MME without this safety reduction can lead to overdose.
For related assessments, see IV Drip Rate, Pediatric Dose and Creatinine Clearance.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
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