Opioid MME Conversion Calculator
Educational use only. This tool estimates daily morphine milligram equivalents (MME) and a theoretical equianalgesic target dose. It is not a prescribing tool and does not replace clinical judgment.
Excludes methadone, transdermal fentanyl, and buprenorphine because conversion is nonlinear or formulation-specific.
| Opioid (oral) | MME Conversion Factor |
|---|
What this opioid conversion chart calculator does
This calculator helps estimate opioid potency by converting a known oral daily dose into MME/day, then estimating a corresponding oral dose of another opioid. MME is commonly used for risk awareness and medication review. It gives one common reference point when comparing different opioids that have different strengths.
In plain language: if two opioid regimens have a similar MME/day, they may have similar overall opioid exposure. However, similar exposure does not guarantee identical pain control or safety.
How the formula works
Step 1: Convert current opioid to MME/day
MME/day = current daily dose (mg/day) × opioid conversion factor
Step 2: Convert MME/day to target opioid
Estimated target dose (mg/day) = MME/day ÷ target opioid factor
Step 3: Apply a safety reduction when rotating opioids
Because of incomplete cross-tolerance, clinicians often reduce the calculated equianalgesic target dose (for example 25% to 50%) and then titrate carefully. This page displays both reduced values for educational context.
Why conversion must be done carefully
- Different opioids affect people differently due to metabolism, genetics, age, organ function, and co-medications.
- Route of administration matters. This calculator is limited to common oral dose factors.
- Dose equivalence is not the same as clinical equivalence. Side effects and analgesia can still differ.
- Rapid or incorrect conversion can lead to oversedation, respiratory depression, withdrawal, or uncontrolled pain.
Key limitations you should know
- This tool is educational and simplified.
- It does not account for PRN timing, formulation differences, renal/hepatic impairment, or drug interactions.
- It does not provide patient-specific medical advice, prescribing instructions, or emergency guidance.
- For any treatment decisions, use institutional protocols and a licensed clinician.
Example conversion
Suppose a regimen includes 20 mg/day of oral oxycodone. Using a factor of 1.5:
- MME/day = 20 × 1.5 = 30 MME/day
- If converting to oral morphine (factor 1), estimated equianalgesic dose = 30 ÷ 1 = 30 mg/day
- With a 25% reduction: 22.5 mg/day
- With a 50% reduction: 15 mg/day
This illustrates method only. Real-world prescribing still requires full clinical assessment and monitoring.
Frequently asked questions
Is MME a perfect measure of risk?
No. It is useful for standardization, but risk depends on many other factors including concurrent sedatives, sleep apnea, opioid tolerance, and overall health status.
Can I use this calculator for methadone or fentanyl patch conversion?
No. Those conversions are complex and dose dependent. They require specific clinical references and close supervision.
Can this calculator replace a pain specialist?
No. It is a quick educational reference, not a clinical decision engine.