Opioid MME Converter (Educational)
What this opiate calculator converter does
This page converts a known daily opioid dose into an estimated morphine milligram equivalent (MME), then translates that MME into an approximate dose of a different opioid. In practical terms, it helps answer the question: “If someone is on X mg/day of one opioid, what is the rough equivalent in another opioid?”
The calculator is intentionally limited to opioids with relatively stable, fixed conversion factors in common references. Some medications (like methadone or transdermal fentanyl) involve non-linear or route-specific conversion rules and are excluded from this simple model.
Why MME is used in opioid conversion
MME is a standardized comparison metric. Since opioids differ in potency, MME gives a common baseline for estimating relative effect and risk.
- Step 1: Convert source opioid dose to MME/day.
- Step 2: Convert MME/day to target opioid dose.
- Step 3: Apply a clinical reduction (often 25–50%) to account for incomplete cross-tolerance.
Formula used by the calculator
MME/day = Source dose (mg/day) × Source conversion factor
Target equivalent (mg/day) = MME/day ÷ Target conversion factor
Reduced starting estimate = Target equivalent × (1 − reduction%)
Supported opioids and factors (oral)
| Opioid | MME Conversion Factor |
|---|---|
| Codeine | 0.15 |
| Tramadol | 0.10 |
| Tapentadol | 0.40 |
| Hydrocodone | 1.00 |
| Morphine | 1.00 |
| Oxycodone | 1.50 |
| Hydromorphone | 4.00 |
| Oxymorphone | 3.00 |
Important clinical limitations
Even a mathematically correct conversion can still be clinically unsafe if used without context. Real-world opioid management requires individualized assessment.
- Age, kidney/liver function, frailty, and respiratory status change risk dramatically.
- Concurrent sedatives (benzodiazepines, alcohol, sleep meds) increase overdose risk.
- Formulation type (immediate vs extended release) matters.
- Pain diagnosis and opioid tolerance are not captured by a simple calculator.
- Methadone, buprenorphine, and fentanyl patch conversions are not linear and need specialist methods.
Best-practice safety checklist
Before converting
- Reconcile all current opioid and non-opioid sedating medications.
- Confirm whether dose entered is truly total daily dose.
- Review contraindications and prior adverse effects.
After converting
- Use conservative starting doses when rotating agents.
- Monitor sedation, breathing, confusion, and pain control closely.
- Educate on overdose warning signs and emergency response.
- Reassess within an appropriate follow-up interval.
Frequently asked questions
Is this calculator for patient self-use?
No. It is educational. Dose decisions should be made by qualified prescribers with full clinical context.
Why no methadone or fentanyl patch conversion?
Those conversions are non-linear and can become unsafe when simplified. This tool avoids false confidence by excluding them.
Does equivalent dose mean equal safety?
No. Two “equivalent” doses can have different side effects and overdose risk depending on patient-specific factors.
Medical disclaimer: This content is informational only and does not substitute for professional medical advice, diagnosis, or treatment.